vodka to prepare

vodka to prepare
Vodka is one of America's most popular liquors. In the past few years high-end vodkas, like Belvedere, Absolut, Ketel One, and Chopin have seen their sales skyrocket. Vodka is a key ingredient in many of the most popular mixed drinks: Bloody Marys, greyhounds, screwdrivers, Cape Cods and Moscow Mules.


Vodka is made from food items containing starches: sugar beet, molasses, rye, potatoes, wheat and other grains. Smoother vodka is made from grains, such as rye or wheat. Rougher variants are made from potato, molasses or sugar beets. As is true in any recipe, quality ingredients going into the mix when combined with proper technique will ensure a quality end-product.


Few vodka drinkers, however, do not realize that they can make this potent potable right in their own homes. All it takes is some patience, equipment and proper distilling skills.


I should warn the reader that the process of making homemade vodka correctly is time consuming and intensive. There is a further warning that the improper preparation of vodka could be harmful to the drinker's health - even resulting in blindness. The making of homemade vodka is not for the beginning distiller. Rather, it is suggested for those who are already experienced in making other alcoholic beverages in their home. For example, vodka distilling is an exciting departure for those already experienced in brewing their own beers, lagers and ales and for the home winemaking enthusiast.


It is recommended that the beginning vodka producer consult with one who has distilled

olympic 2008

"Olympism is a philosophy of life, exalting and combining in a balanced whole the qualities of body, will and mind. Blending sport with culture and education, Olympism seeks to create a way of life based on the joy found in effort, the educational value of good example and respect for universal fundamental ethical principles."(Olympic Charter 2004, Fundamental Principles, paragraph 1)
Pierre de Coubertin regarded himself first and foremost as an educator. As he saw it, sport should form part of every young person’s education, in the same way as science, literature and art. His aim was thereby to offer a harmonious education of the body and mind. The Olympic Games enabled Coubertin to give his educational concept the international visibility and scope it needed. Highlighted by the Games, the concept could become permanent, independent of the holding of the Games. The Olympic Movement upholds Coubertin’s principles. Today, education through Olympism is therefore universal, essentially based on the fundamental human values. Education linked to Olympism involves two orientations:1) Research on Olympism (the academic world)2) Teaching through Olympism (children, adolescents and athletes) - Academic programmes - Youth programmes

The Environment: A TOP Priority

© GE and Coca-Cola

26 October 2007

At the 7th World Conference on Sport and the Environment in Beijing (25th to the 27th October) two of the Olympic Movement’s TOP partners, Coca-Cola and GE will share their expertise with the delegates.

Coca-Cola has been a worldwide Olympic Partner since 1928—longer than any other. Coca-Cola was also one of the first sponsors to support the IOC’s environmental agenda.

At the 2008 Olympic Games in Beijing, Coca-Cola will once again serve the Olympic community with its HFC-free refrigeration equipment, resource-efficient packaging, biodegradable cups and recycling programmes. The company also plans to unveil the expansion of its hybrid diesel fleet of trucks in China and highlight its efforts to reduce travel miles for product deliveries in the country.

In addition, Coca-Cola is focusing a great deal of attention on raising environmental awareness in Beijing and across China. In advance of the Games, the company has launched an ambitious “Save a Barrel of Water” programme in Beijing to help young people understand the value of water conservation in their daily routines. Developed in partnership with the Beijing Organising Committee of the Olympic Games, China’s Ministry of Education and a number of local community organisations, the programme encourages students to work with their families to save fresh water and recycle waste water.

Another strong proponent of water conservation—and, for that matter, renewable energies, desalination, cleaner coal and greenhouse gas reductions—is GE. The company, which became a Worldwide TOP Partner in 2005, offers an array of solutions aimed at addressing the world’s most pressing environmental challenges.

For the 2008 Beijing Olympic Games, GE is providing a number of cutting-edge energy, lighting and water treatment solutions based on ecomagination technologies. In addition to helping the Beijing Organising Committee deliver “green Games” that promote long-term environmental sustainability, these solutions are allowing GE to showcase its business and technology expertise to potential customers in China. According to Peter Foss, GE’s president of Olympic sponsorship, the company’s relationship with the Olympic Movement is helping them achieve that goal. “Our potential customers in China understand the need for green solutions, especially in the areas of water purification and renewable energies. What we are doing with the organising committee in Beijing certainly gets their attention.”

Indeed, it does. GE is currently delivering several large non-Olympic-related ecomagination projects across China. One involves providing water-processing solutions for the Nanpu Waste Water Plant in Tangshan, which allows recycled water to be used to cool equipment at nearby electricity plants. Another involves supplying wind turbines for the Zhangbei and Shangyi power plants north of Beijing, which will generate nearly 80 megawatts of power and eliminate up to 18.3 million tonnes of greenhouse gases.







The TOP Partner programme provides a win-win scenario for all involved. The Olympic Movement benefits from access to cutting-edge technologies, practises and solutions that promote great Games and environmental sustainability. As GE’s Foss explains, “Our association with the Olympic Games provides great opportunities for us to create connections with other companies committed to environmental causes. The IOC is facilitating conversations and providing a great platform for new collaborations.”

shurpanaka golf tips

GOLF RULES

Rule 1 -- The Game
* The holes on the course must be played in order (l through 9, 10 through 18 or 1 through 18). You must always play by the Rules. You are not allowed to change them.
Rule 2 -- Match Play
* In match play, each hole is a separate contest. If you win the first hole, you are "one-up"; if you lose it, you are "one-down"; if you tie it, you are "all-square." * You have won the match when, for example, you are three-up and there are only two holes left to play. * Anyone you are playing against is your "opponent."
Rule 3 -- Stroke Play
* In stroke play, the competitor with the lowest total score for the round (9 or 18 holes) is the winner. * You must play the ball into the hole before starting the next hole. * Anyone you are playing with is a fellow-competitor.
Rules 4 & 5 -- Clubs and the Ball
* You may carry no more than fourteen clubs. * Normally, you may not change balls during the play of a hole. However, if you damage or cut your ball, you may change the ball after first asking your opponent or fellow competitor.
Rule 6 -- Things a Player Should Do
* Read the notices given to you by the tournament officials. * Always use your proper handicap. * Know your tee-time or starting time. * Make sure you play your own ball (put a mark on the ball in case someone else is using an identical ball. * In stroke play, make sure your score for each hole is correct before you turn in your card. * Keep playing unless there is lightning, you are ill or an official tells you to stop.
Rule 7 -- Practice
* You may not hit a practice shot while playing a hole, or from any hazard. Note: Always read the local rules about practice.
Rule 8 -- Advice on How to Play
* During a round, you may not ask anyone except your caddie or partner for advice on how to play. However, you may ask about Rules or the position of hazards or the flagstick. * You may not give advice to your opponent or fellow-competitor
Rule 9 -- Advising Opponent on Strokes Taken
* In match play, you must tell your opponent the number of strokes you have taken if you are asked.
Rule 10 -- When to Play a Shot
* The player who has the lowest score on a hole has the right to play his/her ball first on the next hole. This is called the "honor." * While playing a hole, the player whose ball is farthest from the hole plays first. * In match play, if you play out of turn, your opponent may make you replay your shot. This is not so in stroke play.
Rule 11 -- Teeing Ground
* Tee your ball between the tee-markers or a little behind them. You may tee your ball as far as two club lengths behind the markers. * If your ball accidentally falls off the tee, you may replace it without penalty.
Rule 12 -- Finding Ball in Hazard -- Identifying Ball
* A hazard is any bunker (area of sand) or water hazard (lake, pond, creek, etc). * In a bunker or water hazard, if sand or leaves cover your ball, you may remove enough of the sand or leaves to be able to see a part of the ball. * You may lift your ball to identify it anywhere except in a hazard. You must tell your opponent or fellow competitor before you lift your ball to identify it.
Rule 13 -- Playing the Ball as it Lies on the Course
* You must play the ball as it lies. You may not move it to a better spot. * You may not improve your lie by pressing down behind the ball. The club may be grounded only lightly behind the ball. * You may not improve the area of your intended swing or line of play by bending or breaking anything growing, such as tree limbs or weeds. * In a hazard, you may not touch the sand, ground or water with the club before or during your back swing. * In a hazard, you may not remove loose impediments (natural things such as leaves or twigs) but you may remove obstructions (artificial objects such as bottles or rakes.)
Rule 14 -- Striking the Ball
* You must strike the ball fairly with the head of the club. You may not push, scrape or rake the ball. * You must not hit your ball while it is moving.
Rule 15 -- Playing a Wrong Ball
* In match play, if you play a ball that is not yours, you lose the hole. If you play the wrong ball in a hazard, there is no penalty and you must then play the right ball. * In stroke play, if you play a ball that is not yours, you must take a two-stroke penalty. If you play the wrong ball in a hazard, you must then play out the hole with your own ball. If you do not do so, you are disqualified.
Rule 16 -- The Putting Green
* If any part of your ball is touching the green, it is on the green. * When your ball is on the green, you may brush away leaves and other loose impediments within your line of putt with your hand or a club. Do not fan them with a cap or towel. * You should repair ball marks or old hole plugs if they are within your line of putt, but you may not repair marks made by spikes or shoes. * You may not test the surface of the green by rolling a ball or scraping the surface. * Always mark your ball by putting a small coin or other marker behind it when you want to pick it up to clean or get it out of another player's way.
Rule 17 -- The Flagstick
* If your ball is off the green, there is no penalty if you play and your ball strikes the flagstick, provided no one is holding the flagstick. * If your ball is on the green, do not putt with the flagstick in the hole. Either take the flagstick out or ask another player to hold it and take it out when you play your ball. In match play, if you putt and your ball hits the flagstick when it is in the hole, you lose the hole. In stroke play, you must add two penalty strokes to your score for the hole.
Rule 18 -- Moving the Ball
* If you or your partner move either of your balls on purpose or accidentally, add a penalty stroke to your score, replace and play it. * If someone or something moves your ball other than you or your partner, (an outside agency) there is no penalty, but you must replace it. If the ball is moved by wind or water, you must play it as it lies. * Once you address the ball, if the ball moves, add a penalty stroke and replace the ball. * If you move a loose impediment lying within one club-length of the ball and the ball moves, add a penalty stroke, replace it and play it. On the putting green, there is no penalty.
Rule 19 -- Ball in Motion Deflected or Stopped
* If your ball hits an outside agency, (bird, rake, etc.), it is called a "rub of the green." There is no penalty and the ball is played as it lies. * "Rub of the green." Play the ball as it lies. No penalty. * Hits you, partner, caddie or equipment, you lose the hole. In stroke play, incur a two-stroke penalty. * Hits your opponent, caddie or equipment, you may replay the shot. * Hit fellow competitor, caddie or equipment, no penalty. * If your ball hits you, your partner, your caddie, or your equipment in match play you lose the hole. In stroke play, you are penalized two strokes and you must play your ball as it lies. * If your ball hits your opponent, his caddie, or his equipment, there is no penalty; you may play the ball as it lies or replay the shot. * If your ball hits a fellow competitor, caddie or equipment in stroke play, there is no penalty and the ball is played as it lies. These are the same as outside agencies in stroke play. * If your ball hits another ball and moves it, you must play your ball as it lies. The owner of the other ball must replace it. If your ball is on the green when you play and the ball, which your ball hits, is also on the green, you are penalized two strokes in stroke play. Otherwise, there is no penalty.
Rule 20 -- Lifting and Dropping the Ball
* If you are going to lift your ball under a Rule and the Rule requires that the ball be replaced, you must put a ball-marker behind the ball before you lift it. * When you drop a ball, stand erect, hold your arm out straight and drop it. * If a dropped ball hits the ground and rolls into a hazard, out of a hazard, comes to rest more than two club-lengths from where it first struck a part of the course, nearer the hole or, if you are dropping away from an immovable obstruction or ground under repair, etc., back into the obstruction or ground under repair, you must re-drop. If the same thing happens when you re-drop, you must place the ball where it struck the ground when it was re-dropped.
Rule 21 -- Cleaning the Ball
* You may clean your ball when you are allowed to lift it. On the green a ball may be cleaned when lifted except when it has been lifted to determine if it is unfit or for identification purposes because it interferes with play.
Rule 22 -- Ball Interfering with or Assisting Play
* If another ball interferes with your swing or is in your line of putt, you may ask the owner of the ball to lift it. * If your ball is near the hole and might serve as a backstop for another player, you may lift your ball.
Rule 23 -- Loose Impediments
* Loose impediments are natural objects that are not growing or fixed -- such as leaves, twigs, branches, worms and insects. You may remove a loose impediment except when your ball and the loose impediment lie in a bunker or water hazard. (Exception see Rule 12)
Rule 24 -- Obstructions
* Obstructions are artificial or man-made objects. Bottles, tin cans, rakes, etc., are movable obstructions. Sprinkler heads, shelter houses, cart paths, etc., are Immovable obstructions. * Movable obstructions anywhere on the course may be removed. If the ball moves when moving an obstruction, it must be replaced without penalty. * You may drop your ball away from an immovable obstruction if it interferes with your swing or stance. Find the nearest point not nearer the hole where you can play without interference with your swing or stance. Drop the ball within one club-length of that point. (You may move your ball away from an immovable obstruction if it interferes with your swing or stance.) Note: You should not pick up the ball from an obstruction until you have established the nearest point of relief.
Rule 25 -- Casual Water; Ground Under Repair; Animal Holes
* Casual water is any temporary puddle of water caused by rain or over watering. Ground under repair is any damaged area, which the Committee has marked as such. * If your ball or your stance is in casual water, ground under repair or a burrowing animal hole, you may either play the ball as it lies or find the nearest place not nearer the hole which gives you relief, and drop the ball within one club-length of that place. * If your ball is in casual water, etc., and you cannot find it, determine where the ball entered the area and drop a ball within one club-length of that place without penalty. * If your ball is on the wrong green, find the nearest place off the green, which is not nearer the hole, and drop the ball within one club-length of that place.
Rule 26 -- Water Hazards
* Water hazard margins are identified by yellow stakes or lines. Lateral water hazard margins are identified by red stakes or lines. * If your ball is in a water hazard or a lateral water hazard, you may play it as it lies. If you cannot find it or do not wish to play it, add a penalty stroke and drop and play another ball from where you last played; or drop a ball behind the water hazard as far back as you wish. If you decide to drop behind the hazard, drop the ball so that there is a straight line between the hole, where your ball last crossed the hazard margin and where you drop the ball. If your ball is in a lateral water hazard, you may drop a ball within two club-lengths of where the ball last crossed the hazard margin, no nearer to the hole.
Rule 27 -- Ball Lost or Out of Bounds
* A ball is lost if it is not found within five minutes after you first begin to search. * A ball is out of bounds when all of it lies beyond the inside line of objects such as white stakes, or a fence or wall that marks the playing area. * If your ball is lost or out of bounds, you must add a penalty stroke to your score and play another ball from where you played your last shot. * If you think your ball may be lost or out of bounds, you may play another ball (provisional ball) from the place where your first ball was played. You must tell your opponent or fellow-competitor that you are playing a provisional ball and play it before you look for the first ball. If you cannot find your first ball or if it is out of bounds, you must count the strokes with the first and provisional balls, add a penalty stroke and play out the hole with the provisional ball. If you find your first ball in bounds, continue play with it and pick up the provisional ball.
Rule 28 -- Ball Unplayable
* If your ball is under a tree or in some other bad situation and you decide you cannot play it, add a penalty stroke and do one of the following:
1. Go back to where you played the last shot and play a ball from there
2. Measure two club-lengths from the unplayable lie, drop a ball and play from there
3. Keep the unplayable lie between where you drop the ball and the hole, go back as far as you wish on a straight line and drop and play the ball.
For a complete discussion of the Rules of Golf, visit the USGA's web site

Naya Sreenagar Kolony

                      This is ad is for social welfare , and the events dedicated to poor people

Naya Sreenagar Kolony


On the eve of the Naya Sreenage Kolony’s
20th anniversary , the colony members are
unanimously decided to conduct a mega
Health Camp (poor people) and sport event
in February 2008 Last Week.

So as a Chairman of the Naya Sreenagar Kolony
I am inviting, all the city students
( High School, College, village ) and City Sports Clubs
are Requested to participate in the mega event,
with out and do successful.

                                                                    Sports Events

                                                            1. Cycling                               5. Volley Ball

                                                            2. Foot Ball                           6. Tennis

                                                            3. Cricket                                7. Chess

                                                            4. Hockey                                8. Kabaddi

I Prize for each sport category will be awarded : Rs. 10 Lakhs
II Prize for each sport category will be awarded : Rs. 6 Lakhs
III Prize for each sport category will be awarded : Rs. 4 Lakhs
And consolation prize and Rs. 5,000/- will be
given for all participants

Send your (teams / individual ) detils in the below format,
To following email: nayasreenagar@yahoo.co.in

Sl.                      Name of the Participant/ Sport club         Event    from which         Phone No:  
No.                    Team / Club institution/                                           organization  

------------------------------------------------------------------------------------------------



------------------------------------------------------------------------------------------------

So I requested all of you register your Name/ College / School / Club and send the email us as early as possible.

HR Tips

Naya Sreenagar Kolony

On the eve of the Naya Sreenage Kolony’s
20th anniversary , the colony members are
unanimously decided to conduct a mega
Health Camp (poor people) and sport event
in February 2008 Last Week.

So as a Chairman of the Naya Sreenagar Kolony
I am inviting, all the city students
( High School, College, village ) and City Sports Clubs
are Requested to participate in the mega event,
with out and do successful.

Sports Events

1. Cycling 5. Volley Ball

2. Foot Ball 6. Tennis

3. Cricket 7. Chess

4. Hockey 8. Kabaddi


I Prize for each sport category will be awarded : Rs. 10 Lakhs
II Prize for each sport category will be awarded : Rs. 6 Lakhs
III Prize for each sport category will be awarded : Rs. 4 Lakhs
And consolation prize and Rs. 5,000/- will be
given for all participants

Send your (teams / individual ) detils in the below format,
To following email: nayasreenagar@yahoo.co.in


Sl. Name of the Participant/ Sport Event from which Phone No:
No. Team / Club institution/ club
----------------------------------------------------------------------------------------------------------



------------------------------------------------------------------------------------------------------------

So I requested all of you register your Name/ College / School / Club and send the email us as early as possible.


HR TIPS




hy have you selected to join us?
I always longed to work with a company. I am familiar and whose
products I have used and trusted.
(Narrate briefly how you can prove your statement. Do good research on
the company before facing the interview)
Where do you want to be in 5 years?
I would like to be frank. Judge me from the work and I am sure you will
put me right where I want to be.
Note : Do not over ambitious and speak in a way that you are not
satisfied with your current job which you have applied for.
Describe your ideal career?
Talk of what you enjoy most your skills and natural talents. Do not
specify your goal and any job title.
Tell me something about yourself
Do not just repeat what you have given in your resume. Be ready with
the answer, a talent or something you did out of the ordinary. You can
sound it as unique or give it a touch of your personality.
How did you apply for the job?
Be specific and give a straight answer of how you came to know about
the vacancy. If it was advertised specify how you came across it.
Why do you want to work here?
Have a research done about the company / organization
Give just one or two reasons why you are interested. You can add these
points (1) company's reputation(2) desire to join the specific field
of interest.
Don't you think that you are over qualified for this job?
(This question is put to you to puzzle a candidate. Be calm and answer
the question with a positive and confident approach)
Answer in the negative
My experience and qualification will just help me to do the job better.
Moreover I am at establishing a long term relationship which my
qualification will favor me to handle more responsibilities and help me to
rise to your expectations.
What competition do you see if you take up this job?
When you answer, clearly show that you have researched carefully and
acquired more in-depth knowledge about the company.
Enumerate some positive and negative traits of the company and their
competitions.
Feel confident to show that competition is not an unexpected one.
What would you do if our competitor offer you a job?
Show your confidence in the company's worth, stress the point 'I would
say No' by pointing out some qualities you found out in your research
about the company.
Why are you leaving your current job?
You should give two or three reasons for leaving.
Lack of challenge, focus on the limitations etc. Point out your
ambition to prove your worth confidently.
What salary do you expect?
(This is a tricky question to be answered carefully. Interviewers often
accept people with realistic financial goals.)
If you mention a salary that is low it shows that you are not up to the
mark. If you mention too high you have ruined a chance to get a job.
So the best is to ask for the salary they offer and then show your
capacity, how your experience and qualification rate with what is offered.
What interests you most about the job?
(Show how you believe that you are most suited to the post. If you can
find out an earlier experience it would be fine.)
If you have experience, you can quote some similarities from the past
and how you achieved success.
What is your dream job?
Make the question a chance to display your aptitude that fits the job
you have applied for. Display how your skills can be put into suite the
challenges and modern trends.
Why should we take you?
This is often the concluding Question( Some tips to the answer)
Don'ts : Do not repeat your resume
Do not enumerate your experience
Do's: Prove Your interest
Be positive in your answer
Be prepared with confidence in what you are going to say
Make sure the answer comes from the bottom of your heart.
If you have unlimited time and financial resources how would you spend
them
Even though it is tempting to discuss thing you would do for fun,
answer these questions with strict coherence with the job you have applied
for.
Egg: If you are into teaching, touch on your interest in adult
literary programmers and other teaching oriented aspects.
How is your experience relevant to this job?
Sketch out some similar work which you have done in your previous job.
It should be something justifiable by you, even though others may think
differently.
You can even ask some question where you can prove that your experience
stands in good strand.
How could you enrich your current job?
Design your answer to show that you are still interested in the job and
you point out a few instances where improvements can be made. Convince
the person that you can be relied on and you will not get bored with
what you do with time.
How many days where you absent from work?
Give a solid attendance record. But at the same time show you were not
responsible . Convince that you are willing to take up responsibility.
Egg: I was absent 7 days. 4 days due to conjunctivitis and one day due
to the death of a close relative and 2 days had to accompany my parents
for their check up.
Tell me about a time you had to deal with an irritate customer, how did
you handle the solution?
The question is aimed at you to hear from yourself how you handle
people when others loose their temper. Here the best answer you can give to
describe a situation and show how you handled it with maturity and
diplomacy.
How do you manage stress in your daily work?
You can describe a situation of how you had managed stress in your
previous work if you had one or narrate how you can find time in your busy
schedule to relax a bit.
Describe a professional skill you have developed in you?
It will be better if you be specific with your answer. Narrate some
thing you worked for to fulfill your work more efficiently. Describe how
you attended a seminar and brought about the changed in your work.
How do you manage your work to meet dead lines
Answer the question effectively . Describe in detail how your plan
out, set priorities, determine schedules, how you follow out to see the
progress and meet the dead line.
What books you read?
Do not ever say you have read a book which you have not. Here your
suggestion can lead the interviewer to know your taste and interest. It can
also hint on how you take your profession.
What are the most rewarding aspect of you most recent job?
The best way to answer it is to focus in what you do efficiently, keep
in mind the position you are applying for.
What aspects of this job do you feel most confident?
Narrate what you are good and match it with the present job
requirements. You may ask questions to clear if that particular skill will add
benefit to the company
What can motivate you?
The Interview expects an answer to know you better .Keep in tune with
your job and work you have applied for. Do not beat around the bush.
Whom do you choose as your reference and why?
Name the references and how you know them. You can also show that you
are a person who care for relationships and how you stand in good stead
with them.
Can we call all your references?
If you have given your present boss as your reference you can tell that
you prefer to call your current boss only after you receive a
confirmed offer as he may not like you changing the job.
Do you have any questions?
Be prepared to answer this question in advance. List out a few
questions you wish to know more about. After you have faced the interview your
logic will guide you to ask the question you really want to know more
about.
How do you handle criticism
Here the interview is on the look out for your accountability and
professional character.
Simply explain a situation that caused a problem and narrate how you
faced it and overcame it.
Tell me about a situation that upset you at work
Her the interview is trying to find out how you deal with pressure. Be
diplomatic and objective with your answer. Prepare the answer so that
the answer comes as a smooth reassurance
Have you ever been fired?
If the answer is negative, the answer is simple. But if you have been
fired, you need to be prepared to the answer the follow up questions
that my come up.
If the termination was for reason beyond your control narrate it. If
not do not try justifying yourself. If you had a fault, admit it and
convince the interview that you have corrected it.
Do you change your job frequently?
Be honest and if you had changed the jobs frequently there could be
ample reasons to do so. Put them up as contracts that expired at the
stipulated time.
Be convincing when you say that you long to have a steady and long
lasting relationship with the present job you are applying for.
What is the toughest job you had?
Avoid making any negative statements especially about your previous
employer. Change the question with a positive outlook and answer it with a
satisfied remark of your outcome.
How do you handle tension?
Answer with ease that in any job and any situation that tension is a
part of it. Relax before putting the f act you are very used to such
type of works.
What is your current salary?
Do not bluff. Be specific on the answer. Do not hesitate to say the
benefits you enjoyed in the previous job. It may be verified so never
mention the benefits you have not got.
Will you be willing to accept transfer?
Tell you preference but do not specify that you will be not willing to
work else where.
What is your weakness?
Turn the question to a positive one. Simply say that you are a
perfectionist and your commitment to output of high quality perfect work. Say
this is your weakness.

C Interview Questions and Answers

$$ $$



Section 1. Declarations and Initializations

1.1: How do you decide which integer type to use?

A: If you might need large values (tens of thousands), use long.
Otherwise, if space is very important, use short. Otherwise,
use int.

1.4: What should the 64-bit type on a machine that can support it?

A: C9X specifies long long.

1.7: What's the best way to declare and define global variables?

A: The best arrangement is to place each definition in some
relevant .c file, with an external declaration in a header file.

1.11: What does extern mean in a function declaration?

A: Nothing, really; the keyword extern is optional here.

1.12: What's the auto keyword good for?

A: Nothing.

1.14: I can't seem to define a linked list node which contains a
pointer to itself.

A: Structures in C can certainly contain pointers to themselves;
the discussion and example in section 6.5 of K&R make this
clear. Problems arise if an attempt is made to define (and use)
a typedef in the midst of such a declaration; avoid this.

1.21: How do I declare an array of N pointers to functions returning
pointers to functions returning pointers to characters?

A: char *(*(*a[N])())();
Using a chain of typedefs, or the cdecl program, makes these
declarations easier.

1.22: How can I declare a function that returns a pointer to a
function of its own type?

A: You can't quite do it directly. Use a cast, or wrap a struct
around the pointer and return that.

1.25: My compiler is complaining about an invalid redeclaration of a
function, but I only define it once.

A: Calling an undeclared function declares it implicitly as
returning int.

1.25b: What's the right declaration for main()?

A: See questions 11.12a to 11.15.

1.30: What am I allowed to assume about the initial values
of variables which are not explicitly initialized?

A: Uninitialized variables with "static" duration start out as 0,
as if the programmer had initialized them. Variables with
"automatic" duration, and dynamically-allocated memory, start
out containing garbage (with the exception of calloc).

1.31: Why can't I initialize a local array with a string?

A: Perhaps you have a pre-ANSI compiler.

1.31b: What's wrong with "char *p = malloc(10);" ?

A: Function calls are not allowed in initializers for global or
static variables.

1.32: What is the difference between char a[] = "string"; and
char *p = "string"; ?

A: The first declares an initialized and modifiable array; the
second declares a pointer initialized to a not-necessarily-
modifiable constant string.

1.34: How do I initialize a pointer to a function?

A: Use something like "extern int func(); int (*fp)() = func;" .


Section 2. Structures, Unions, and Enumerations

2.1: What's the difference between struct x1 { ... }; and
typedef struct { ... } x2; ?

A: The first structure is named by a tag, the second by a typedef
name.

2.2: Why doesn't "struct x { ... }; x thestruct;" work?

A: C is not C++.

2.3: Can a structure contain a pointer to itself?

A: See question 1.14.

2.4: What's the best way of implementing opaque (abstract) data types
in C?

A: One good way is to use structure pointers which point to
structure types which are not publicly defined.

2.6: I came across some code that declared a structure with the last
member an array of one element, and then did some tricky
allocation to make it act like the array had several elements.
Is this legal or portable?

A: An official interpretation has deemed that it is not strictly
conforming with the C Standard.

2.7: I heard that structures could be assigned to variables and
passed to and from functions, but K&R1 says not.

A: These operations are supported by all modern compilers.

2.8: Is there a way to compare structures automatically?

A: No.

2.10: Can I pass constant values to functions which accept structure
arguments?

A: Not yet. As of this writing, C has no way of generating
anonymous structure values.

2.11: How can I read/write structures from/to data files?

A: It is relatively straightforward to use fread and fwrite.

2.12: How can I turn off structure padding?

A: There is no standard method.

2.13: Why does sizeof report a larger size than I expect for a
structure type?

A: The alignment of arrays of structures must be preserved.

2.14: How can I determine the byte offset of a field within a
structure?

A: ANSI C defines the offsetof() macro, which should be used if
available.

2.15: How can I access structure fields by name at run time?

A: Build a table of names and offsets, using the offsetof() macro.

2.18: I have a program which works correctly, but dumps core after it
finishes. Why?

A: Check to see if a structure type declaration just before main()
is missing its trailing semicolon, causing main() to be declared
as returning a structure. See also questions 10.9 and 16.4.

2.20: Can I initialize unions?

A: The current C Standard allows an initializer for the first-named
member.

2.22: What is the difference between an enumeration and a set of
preprocessor #defines?

A: At the present time, there is little difference. The C Standard
states that enumerations are compatible with integral types.

2.24: Is there an easy way to print enumeration values symbolically?

A: No.


Section 3. Expressions

3.1: Why doesn't the code "a[i] = i++;" work?

A: The variable i is both referenced and modified in the same
expression.

3.2: Under my compiler, the code "int i = 7;
printf("%d\n", i++ * i++);" prints 49. Regardless of the order
of evaluation, shouldn't it print 56?

A: The operations implied by the postincrement and postdecrement
operators ++ and -- are performed at some time after the
operand's former values are yielded and before the end of the
expression, but not necessarily immediately after, or before
other parts of the expression are evaluated.

3.3: What should the code "int i = 3; i = i++;" do?

A: The expression is undefined.

3.3b: Here's a slick expression: "a ^= b ^= a ^= b". It swaps a and b
without using a temporary.

A: Not portably; its behavior is undefined.

3.4: Don't precedence and parentheses dictate order of evaluation?

A: Operator precedence and explicit parentheses impose only a
partial ordering on the evaluation of an expression, which does
not generally include the order of side effects.

3.5: But what about the && and || operators?

A: There is a special exception for those operators: left-to-right
evaluation is guaranteed.

3.8: What's a "sequence point"?

A: A point (at the end of a full expression, or at the ||, &&, ?:,
or comma operators, or just before a function call) at which all
side effects are guaranteed to be complete.

3.9: So given a[i] = i++; we don't know which cell of a[] gets
written to, but i does get incremented by one, right?

A: *No*. Once an expression or program becomes undefined, *all*
aspects of it become undefined.

3.12: If I'm not using the value of the expression, should I use i++
or ++i to increment a variable?

A: Since the two forms differ only in the value yielded, they are
entirely equivalent when only their side effect is needed.

3.14: Why doesn't the code "int a = 1000, b = 1000;
long int c = a * b;" work?

A: You must manually cast one of the operands to (long).

3.16: Can I use ?: on the left-hand side of an assignment expression?

A: No.


Section 4. Pointers

4.2: What's wrong with "char *p; *p = malloc(10);"?

A: The pointer you declared is p, not *p.

4.3: Does *p++ increment p, or what it points to?

A: *p++ increments p. To increment the value pointed to by p, use
(*p)++ .

4.5: I want to use a char * pointer to step over some ints. Why
doesn't "((int *)p)++;" work?

A: In C, a cast operator is a conversion operator, and by
definition it yields an rvalue, which cannot be assigned to, or
incremented with ++.

4.8: I have a function which accepts, and is supposed to initialize,
a pointer, but the pointer in the caller remains unchanged.

A: The called function probably altered only the passed copy of the
pointer.

4.9: Can I use a void ** pointer as a parameter so that a function
can accept a generic pointer by reference?

A: Not portably.

4.10: I have a function which accepts a pointer to an int. How can I
pass a constant like 5 to it?

A: You will have to declare a temporary variable.

4.11: Does C even have "pass by reference"?

A: Not really, though it can be simulated.

4.12: I've seen different methods used for calling functions via
pointers.

A: The extra parentheses and explicit * are now officially
optional, although some older implementations require them.


Section 5. Null Pointers

5.1: What is this infamous null pointer, anyway?

A: For each pointer type, there is a special value -- the "null
pointer" -- which is distinguishable from all other pointer
values and which is not the address of any object or function.

5.2: How do I get a null pointer in my programs?

A: A constant 0 in a pointer context is converted into a null
pointer at compile time. A "pointer context" is an
initialization, assignment, or comparison with one side a
variable or expression of pointer type, and (in ANSI standard C)
a function argument which has a prototype in scope declaring a
certain parameter as being of pointer type. In other contexts
(function arguments without prototypes, or in the variable part
of variadic function calls) a constant 0 with an appropriate
explicit cast is required.

5.3: Is the abbreviated pointer comparison "if(p)" to test for non-
null pointers valid?

A: Yes. The construction "if(p)" works, regardless of the internal
representation of null pointers, because the compiler
essentially rewrites it as "if(p != 0)" and goes on to convert 0
into the correct null pointer.

5.4: What is NULL and how is it #defined?

A: NULL is simply a preprocessor macro, #defined as 0 (or
((void *)0)), which is used (as a stylistic convention, in
preference to unadorned 0's) to generate null pointers.

5.5: How should NULL be defined on a machine which uses a nonzero bit
pattern as the internal representation of a null pointer?

A: The same as on any other machine: as 0. (The compiler makes the
translation, upon seeing a 0, not the preprocessor; see also
question 5.4.)

5.6: If NULL were defined as "((char *)0)," wouldn't that make
function calls which pass an uncast NULL work?

A: Not in general. The complication is that there are machines
which use different internal representations for pointers to
different types of data. A cast is still required to tell the
compiler which kind of null pointer is required, since it may be
different from (char *)0.

5.9: If NULL and 0 are equivalent as null pointer constants, which
should I use?

A: Either; the distinction is entirely stylistic.

5.10: But wouldn't it be better to use NULL, in case the value of NULL
changes?

A: No. NULL is a constant zero, so a constant zero is equally
sufficient.

5.12: I use the preprocessor macro "#define Nullptr(type) (type *)0"
to help me build null pointers of the correct type.

A: This trick, though valid, does not buy much.

5.13: This is strange. NULL is guaranteed to be 0, but the null
pointer is not?

A: A "null pointer" is a language concept whose particular internal
value does not matter. A null pointer is requested in source
code with the character "0". "NULL" is a preprocessor macro,
which is always #defined as 0 (or ((void *)0)).

5.14: Why is there so much confusion surrounding null pointers?

A: The fact that null pointers are represented both in source code,
and internally to most machines, as zero invites unwarranted
assumptions. The use of a preprocessor macro (NULL) may seem to
suggest that the value could change some day, or on some weird
machine.

5.15: I'm confused. I just can't understand all this null pointer
stuff.

A: A simple rule is, "Always use `0' or `NULL' for null pointers,
and always cast them when they are used as arguments in function
calls."

5.16: Given all the confusion surrounding null pointers, wouldn't it
be easier simply to require them to be represented internally by
zeroes?

A: Such a requirement would accomplish little.

5.17: Seriously, have any actual machines really used nonzero null
pointers?

A: Machines manufactured by Prime, Honeywell-Bull, and CDC, as well
as Symbolics Lisp Machines, have done so.

5.20: What does a run-time "null pointer assignment" error mean?

A: It means that you've written, via a null pointer, to an invalid
location. (See also question 16.8.)


Section 6. Arrays and Pointers

6.1: I had the definition char a[6] in one source file, and in
another I declared extern char *a. Why didn't it work?

A: The declaration extern char *a simply does not match the actual
definition. Use extern char a[].

6.2: But I heard that char a[] was identical to char *a.

A: Not at all. Arrays are not pointers. A reference like x[3]
generates different code depending on whether x is an array or a
pointer.

6.3: So what is meant by the "equivalence of pointers and arrays" in
C?

A: An lvalue of type array-of-T which appears in an expression
decays into a pointer to its first element; the type of the
resultant pointer is pointer-to-T. So for an array a and
pointer p, you can say "p = a;" and then p[3] and a[3] will
access the same element.

6.4: Why are array and pointer declarations interchangeable as
function formal parameters?

A: It's supposed to be a convenience.

6.7: How can an array be an lvalue, if you can't assign to it?

A: An array is not a "modifiable lvalue."

6.8: What is the real difference between arrays and pointers?

A: Arrays automatically allocate space which is fixed in size and
location; pointers are dynamic.

6.9: Someone explained to me that arrays were really just constant
pointers.

A: An array name is "constant" in that it cannot be assigned to,
but an array is *not* a pointer.

6.11: I came across some "joke" code containing the "expression"
5["abcdef"] . How can this be legal C?

A: Yes, array subscripting is commutative in C. The array
subscripting operation a[e] is defined as being identical to
*((a)+(e)).

6.12: What's the difference between array and &array?

A: The type.

6.13: How do I declare a pointer to an array?

A: Usually, you don't want to. Consider using a pointer to one of
the array's elements instead.

6.14: How can I set an array's size at run time?

A: It's straightforward to use malloc() and a pointer.

6.15: How can I declare local arrays of a size matching a passed-in
array?

A: Until recently, you couldn't; array dimensions had to be compile-
time constants. C9X will fix this.

6.16: How can I dynamically allocate a multidimensional array?

A: The traditional solution is to allocate an array of pointers,
and then initialize each pointer to a dynamically-allocated
"row." See the full list for code samples.

6.17: Can I simulate a non-0-based array with a pointer?

A: Not if the pointer points outside of the block of memory it is
intended to access.

6.18: My compiler complained when I passed a two-dimensional array to
a function expecting a pointer to a pointer.

A: The rule by which arrays decay into pointers is not applied
recursively. An array of arrays (i.e. a two-dimensional array
in C) decays into a pointer to an array, not a pointer to a
pointer.

6.19: How do I write functions which accept two-dimensional arrays
when the width is not known at compile time?

A: It's not always particularly easy.

6.20: How can I use statically- and dynamically-allocated
multidimensional arrays interchangeably when passing them to
functions?

A: There is no single perfect method, but see the full list for
some ideas.

6.21: Why doesn't sizeof properly report the size of an array which is
a parameter to a function?

A: The sizeof operator reports the size of the pointer parameter
which the function actually receives.


Section 7. Memory Allocation

7.1: Why doesn't the code "char *answer; gets(answer);" work?

A: The pointer variable answer has not been set to point to any
valid storage. The simplest way to correct this fragment is to
use a local array, instead of a pointer.

7.2: I can't get strcat() to work. I tried "char *s3 =
strcat(s1, s2);" but I got strange results.

A: Again, the main problem here is that space for the concatenated
result is not properly allocated.

7.3: But the man page for strcat() says that it takes two char *'s as
arguments. How am I supposed to know to allocate things?

A: In general, when using pointers you *always* have to consider
memory allocation, if only to make sure that the compiler is
doing it for you.

7.3b: I just tried the code "char *p; strcpy(p, "abc");" and it
worked. Why didn't it crash?

A: You got "lucky".

7.3c: How much memory does a pointer variable allocate?

A: Only enough memory to hold the pointer itself, not any memory
for the pointer to point to.

7.5a: I have a function that is supposed to return a string, but when
it returns to its caller, the returned string is garbage.

A: Make sure that the pointed-to memory is properly (i.e. not
locally) allocated.

7.5b: So what's the right way to return a string?

A: Return a pointer to a statically-allocated buffer, a buffer
passed in by the caller, or memory obtained with malloc().

7.6: Why am I getting "warning: assignment of pointer from integer
lacks a cast" for calls to malloc()?

A: Have you #included ?

7.7: Why does some code carefully cast the values returned by malloc
to the pointer type being allocated?

A: Before ANSI/ISO C, these casts were required to silence certain
warnings.

7.8: Why does so much code leave out the multiplication by
sizeof(char) when allocating strings?

A: Because sizeof(char) is, by definition, exactly 1.

7.14: I've heard that some operating systems don't actually allocate
malloc'ed memory until the program tries to use it. Is this
legal?

A: It's hard to say.

7.16: I'm allocating a large array for some numeric work, but malloc()
is acting strangely.

A: Make sure the number you're trying to pass to malloc() isn't
bigger than a size_t can hold.

7.17: I've got 8 meg of memory in my PC. Why can I only seem to
malloc 640K or so?

A: Under the segmented architecture of PC compatibles, it can be
difficult to use more than 640K with any degree of transparency.
See also question 19.23.

7.19: My program is crashing, apparently somewhere down inside malloc.

A: Make sure you aren't using more memory than you malloc'ed,
especially for strings (which need strlen(str) + 1 bytes).

7.20: You can't use dynamically-allocated memory after you free it,
can you?

A: No. Some early documentation implied otherwise, but the claim
is no longer valid.

7.21: Why isn't a pointer null after calling free()?

A: C's pass-by-value semantics mean that called functions can never
permanently change the values of their arguments.

7.22: When I call malloc() to allocate memory for a local pointer, do
I have to explicitly free() it?

A: Yes.

7.23: When I free a dynamically-allocated structure containing
pointers, do I also have to free each subsidiary pointer?

A: Yes.

7.24: Must I free allocated memory before the program exits?

A: You shouldn't have to.

7.25: Why doesn't my program's memory usage go down when I free
memory?

A: Most implementations of malloc/free do not return freed memory
to the operating system.

7.26: How does free() know how many bytes to free?

A: The malloc/free implementation remembers the size of each block
as it is allocated.

7.27: So can I query the malloc package to find out how big an
allocated block is?

A: Not portably.

7.30: Is it legal to pass a null pointer as the first argument to
realloc()?

A: ANSI C sanctions this usage, although several earlier
implementations do not support it.

7.31: What's the difference between calloc() and malloc()?

A: calloc() takes two arguments, and initializes the allocated
memory to all-bits-0.

7.32: What is alloca() and why is its use discouraged?

A: alloca() allocates memory which is automatically freed when the
function which called alloca() returns. alloca() cannot be
written portably, is difficult to implement on machines without
a stack, and fails under certain conditions if implemented
simply.


Section 8. Characters and Strings

8.1: Why doesn't "strcat(string, '!');" work?

A: strcat() concatenates *strings*, not characters.

8.2: Why won't the test if(string == "value") correctly compare
string against the value?

A: It's comparing pointers. To compare two strings, use strcmp().

8.3: Why can't I assign strings to character arrays?

A: Strings are arrays, and you can't assign arrays directly. Use
strcpy() instead.

8.6: How can I get the numeric (character set) value corresponding to
a character?

A: In C, if you have the character, you have its value.

8.9: Why is sizeof('a') not 1?

A: Character constants in C are of type int.


Section 9. Boolean Expressions and Variables

9.1: What is the right type to use for Boolean values in C?

A: There's no one right answer; see the full list for some
discussion.

9.2: What if a built-in logical or relational operator "returns"
something other than 1?

A: When a Boolean value is generated by a built-in operator, it is
guaranteed to be 1 or 0. (This is *not* true for some library
routines such as isalpha.)

9.3: Is if(p), where p is a pointer, valid?

A: Yes. See question 5.3.


Section 10. C Preprocessor

10.2: I've got some cute preprocessor macros that let me write C code
that looks more like Pascal. What do y'all think?

A: Bleah.

10.3: How can I write a generic macro to swap two values?

A: There is no good answer to this question. The best all-around
solution is probably to forget about using a macro.

10.4: What's the best way to write a multi-statement macro?

A: #define Func() do {stmt1; stmt2; ... } while(0) /* (no trailing ;) */

10.6: What are .h files and what should I put in them?

A: Header files (also called ".h files") should generally contain
common declarations and macro, structure, and typedef
definitions, but not variable or function definitions.

10.7: Is it acceptable for one header file to #include another?

A: It's a question of style, and thus receives considerable debate.

10.8a: What's the difference between #include <> and #include "" ?

A: Roughly speaking, the <> syntax is for Standard headers and ""
is for project headers.

10.8b: What are the complete rules for header file searching?

A: The exact behavior is implementation-defined; see the full list
for some discussion.

10.9: I'm getting strange syntax errors on the very first declaration
in a file, but it looks fine.

A: Perhaps there's a missing semicolon at the end of the last
declaration in the last header file you're #including.

10.10b: I'm #including the header file for a function, but the linker
keeps saying it's undefined.

A: See question 13.25.

10.11: Where can I get a copy of a missing header file?

A: Contact your vendor, or see question 18.16 or the full list.

10.12: How can I construct preprocessor #if expressions which compare
strings?

A: You can't do it directly; try #defining several manifest
constants and implementing conditionals on those.

10.13: Does the sizeof operator work in preprocessor #if directives?

A: No.

10.14: Can I use an #ifdef in a #define line, to define something two
different ways?

A: No.

10.15: Is there anything like an #ifdef for typedefs?

A: Unfortunately, no.

10.16: How can I use a preprocessor #if expression to detect
endianness?

A: You probably can't.

10.18: How can I preprocess some code to remove selected conditional
compilations, without preprocessing everything?

A: Look for a program called unifdef, rmifdef, or scpp.

10.19: How can I list all of the predefined identifiers?

A: If the compiler documentation is unhelpful, try extracting
printable strings from the compiler or preprocessor executable.

10.20: I have some old code that tries to construct identifiers with a
macro like "#define Paste(a, b) a/**/b", but it doesn't work any
more.

A: Try the ANSI token-pasting operator ##.

10.22: What does the message "warning: macro replacement within a
string literal" mean?

A: See question 11.18.

10.23-4: I'm having trouble using macro arguments inside string
literals, using the `#' operator.

A: See questions 11.17 and 11.18.

10.25: I've got this tricky preprocessing I want to do and I can't
figure out a way to do it.

A: Consider writing your own little special-purpose preprocessing
tool, instead.

10.26: How can I write a macro which takes a variable number of
arguments?

A: Here is one popular trick. Note that the parentheses around
printf's argument list are in the macro call, not the
definition.

#define DEBUG(args) (printf("DEBUG: "), printf args)

if(n != 0) DEBUG(("n is %d\n", n));


Section 11. ANSI/ISO Standard C

11.1: What is the "ANSI C Standard?"

A: In 1983, the American National Standards Institute (ANSI)
commissioned a committee to standardize the C language. Their
work was ratified as ANS X3.159-1989, and has since been adopted
as ISO/IEC 9899:1990, and later amended.

11.2: How can I get a copy of the Standard?

A: Copies are available from ANSI in New York, or from Global
Engineering Documents in Englewood, CO, or from any national
standards body, or from ISO in Geneva, or republished within one
or more books. See the unabridged list for details.

11.2b: Where can I get information about updates to the Standard?

A: See the full list for pointers.

11.3: My ANSI compiler is complaining about prototype mismatches for
parameters declared float.

A: You have mixed the new-style prototype declaration
"extern int func(float);" with the old-style definition
"int func(x) float x;". "Narrow" types are treated differently
according to which syntax is used. This problem can be fixed by
avoiding narrow types, or by using either new-style (prototype)
or old-style syntax consistently.

11.4: Can you mix old-style and new-style function syntax?

A: Doing so is currently legal, for most argument types
(see question 11.3).

11.5: Why does the declaration "extern int f(struct x *p);" give me a
warning message?

A: A structure declared (or even mentioned) for the first time
within a prototype cannot be compatible with other structures
declared in the same source file.

11.8: Why can't I use const values in initializers and array
dimensions?

A: The value of a const-qualified object is *not* a constant
expression in the full sense of the term.

11.9: What's the difference between "const char *p" and
"char * const p"?

A: The former declares a pointer to a constant character; the
latter declares a constant pointer to a character.

11.10: Why can't I pass a char ** to a function which expects a
const char **?

A: The rule which permits slight mismatches in qualified pointer
assignments is not applied recursively.

11.12a: What's the correct declaration of main()?

A: int main(int argc, char *argv[]) .

11.12b: Can I declare main() as void, to shut off these annoying "main
returns no value" messages?

A: No.

11.13: But what about main's third argument, envp?

A: It's a non-standard (though common) extension.

11.14: I believe that declaring void main() can't fail, since I'm
calling exit() instead of returning.

A: It doesn't matter whether main() returns or not, the problem is
that its caller may not even be able to *call* it correctly.

11.15: The book I've been using always uses void main().

A: It's wrong.

11.16: Is exit(status) truly equivalent to returning the same status
from main()?

A: Yes and no. (See the full list for details.)

11.17: How do I get the ANSI "stringizing" preprocessing operator `#'
to stringize the macro's value instead of its name?

A: You can use a two-step #definition to force a macro to be
expanded as well as stringized.

11.18: What does the message "warning: macro replacement within a
string literal" mean?

A: Some pre-ANSI compilers/preprocessors expanded macro parameters
even inside string literals and character constants.

11.19: I'm getting strange syntax errors inside lines I've #ifdeffed
out.

A: Under ANSI C, #ifdeffed-out text must still consist of "valid
preprocessing tokens." This means that there must be no
newlines inside quotes, and no unterminated comments or quotes
(i.e. no single apostrophes).

11.20: What are #pragmas ?

A: The #pragma directive provides a single, well-defined "escape
hatch" which can be used for extensions.

11.21: What does "#pragma once" mean?

A: It is an extension implemented by some preprocessors to help
make header files idempotent.

11.22: Is char a[3] = "abc"; legal?

A: Yes, in ANSI C.

11.24: Why can't I perform arithmetic on a void * pointer?

A: The compiler doesn't know the size of the pointed-to objects.

11.25: What's the difference between memcpy() and memmove()?

A: memmove() offers guaranteed behavior if the source and
destination arguments overlap.

11.26: What should malloc(0) do?

A: The behavior is implementation-defined.

11.27: Why does the ANSI Standard not guarantee more than six case-
insensitive characters of external identifier significance?

A: The problem is older linkers which cannot be forced (by mere
words in a Standard) to upgrade.

11.29: My compiler is rejecting the simplest possible test programs,
with all kinds of syntax errors.

A: Perhaps it is a pre-ANSI compiler.

11.30: Why are some ANSI/ISO Standard library functions showing up as
undefined, even though I've got an ANSI compiler?

A: Perhaps you don't have ANSI-compatible headers and libraries.

11.31: Does anyone have a tool for converting old-style C programs to
ANSI C, or for automatically generating prototypes?

A: See the full list for details.

11.32: Why won't frobozz-cc, which claims to be ANSI compliant, accept
this code?

A: Are you sure that the code being rejected doesn't rely on some
non-Standard extension?

11.33: What's the difference between implementation-defined,
unspecified, and undefined behavior?

A: If you're writing portable code, ignore the distinctions.
Otherwise, see the full list.

11.34: I'm appalled that the ANSI Standard leaves so many issues
undefined.

A: In most of these cases, the Standard is simply codifying
existing practice.

11.35: I just tried some allegedly-undefined code on an ANSI-conforming
compiler, and got the results I expected.

A: A compiler may do anything it likes when faced with undefined
behavior, including doing what you expect.


Section 12. Stdio

12.1: What's wrong with the code "char c; while((c = getchar()) !=
EOF) ..."?

A: The variable to hold getchar's return value must be an int.

12.2: Why won't the code "while(!feof(infp)) {
fgets(buf, MAXLINE, infp); fputs(buf, outfp); }" work?

A: EOF is only indicated *after* an input routine fails.

12.4: My program's prompts and intermediate output don't always show
up on the screen.

A: It's best to use an explicit fflush(stdout) whenever output
should definitely be visible.

12.5: How can I read one character at a time, without waiting for the
RETURN key?

A: See question 19.1.

12.6: How can I print a '%' character with printf?

A: "%%".

12.9: How can printf() use %f for type double, if scanf() requires
%lf?

A: C's "default argument promotions" mean that values of type float
are promoted to double.

12.9b: What printf format should I use for a typedef when I don't know
the underlying type?

A: Use a cast to convert the value to a known type, then use the
printf format matching that type.

12.10: How can I implement a variable field width with printf?

A: Use printf("%*d", width, x).

12.11: How can I print numbers with commas separating the thousands?

A: There is no standard routine (but see ).

12.12: Why doesn't the call scanf("%d", i) work?

A: The arguments you pass to scanf() must always be pointers.

12.13: Why doesn't the code "double d; scanf("%f", &d);" work?

A: Unlike printf(), scanf() uses %lf for double, and %f for float.

12.15: How can I specify a variable width in a scanf() format string?

A: You can't.

12.17: When I read numbers from the keyboard with scanf "%d\n", it
seems to hang until I type one extra line of input.

A: Try using "%d" instead of "%d\n".

12.18: I'm reading a number with scanf %d and then a string with
gets(), but the compiler seems to be skipping the call to
gets()!

A: scanf() and gets() do not work well together.

12.19: I'm re-prompting the user if scanf() fails, but sometimes it
seems to go into an infinite loop.

A: scanf() tends to "jam" on bad input since it does not discard
it.

12.20: Why does everyone say not to use scanf()? What should I use
instead?

A: scanf() has a number of problems. Usually, it's easier to read
entire lines and then interpret them.

12.21: How can I tell how much destination buffer space I'll need for
an arbitrary sprintf call? How can I avoid overflowing the
destination buffer with sprintf()?

A: Use the new snprintf() function, if you can.

12.23: Why does everyone say not to use gets()?

A: It cannot be prevented from overflowing the input buffer.

12.24: Why does errno contain ENOTTY after a call to printf()?

A: Don't worry about it. It is only meaningful for a program to
inspect the contents of errno after an error has been reported.

12.25: What's the difference between fgetpos/fsetpos and ftell/fseek?

A: fgetpos() and fsetpos() use a special typedef which may allow
them to work with larger files than ftell() and fseek().

12.26: Will fflush(stdin) flush unread characters from the standard
input stream?

A: No.

12.30: I'm trying to update a file in place, by using fopen mode "r+",
but it's not working.

A: Be sure to call fseek between reading and writing.

12.33: How can I redirect stdin or stdout from within a program?

A: Use freopen().

12.34: Once I've used freopen(), how can I get the original stream
back?

A: There isn't a good way. Try avoiding freopen.

12.36b: How can I arrange to have output go two places at once?

A: You could write your own printf variant which printed everything
twice. See question 15.5.

12.38: How can I read a binary data file properly?

A: Be sure to specify "rb" mode when calling fopen().


Section 13. Library Functions

13.1: How can I convert numbers to strings?

A: Just use sprintf().

13.2: Why does strncpy() not always write a '\0'?

A: For mildly-interesting historical reasons.

13.5: Why do some versions of toupper() act strangely if given an
upper-case letter?

A: Older versions of toupper() and tolower() did not always work as
expected in this regard.

13.6: How can I split up a string into whitespace-separated fields?

A: Try strtok().

13.7: I need some code to do regular expression and wildcard matching.

A: regexp libraries abound; see the full list for details.

13.8: I'm trying to sort an array of strings with qsort(), using
strcmp() as the comparison function, but it's not working.

A: You'll have to write a "helper" comparison function which takes
two generic pointer arguments, converts them to char **, and
dereferences them, yielding char *'s which can be usefully
compared.

13.9: Now I'm trying to sort an array of structures, but the compiler
is complaining that the function is of the wrong type for
qsort().

A: The comparison function must be declared as accepting "generic
pointers" (const void *) which it then converts to structure
pointers.

13.10: How can I sort a linked list?

A: Algorithms like insertion sort and merge sort work well, or you
can keep the list in order as you build it.

13.11: How can I sort more data than will fit in memory?

A: You want an "external sort"; see the full list for details.

13.12: How can I get the time of day in a C program?

A: Just use the time(), ctime(), localtime() and/or strftime()
functions.

13.13: How can I convert a struct tm or a string into a time_t?

A: The ANSI mktime() function converts a struct tm to a time_t. No
standard routine exists to parse strings.

13.14: How can I perform calendar manipulations?

A: The ANSI/ISO Standard C mktime() and difftime() functions
provide some support for both problems.

13.14b: Does C have any Year 2000 problems?

A: No, although poorly-written C programs do. Make sure you know
that tm_year holds the value of the year minus 1900.

13.15: I need a random number generator.

A: The Standard C library has one: rand().

13.16: How can I get random integers in a certain range?

A: One method is something like

(int)((double)rand() / ((double)RAND_MAX + 1) * N)

13.17: Each time I run my program, I get the same sequence of numbers
back from rand().

A: You can call srand() to seed the pseudo-random number generator
with a truly random initial value.

13.18: I need a random true/false value, so I'm just taking rand() % 2,
but it's alternating 0, 1, 0, 1, 0...

A: Try using the higher-order bits: see question 13.16.

13.20: How can I generate random numbers with a normal or Gaussian
distribution?

A: See the longer versions of this list for ideas.

13.24: I'm trying to port this old program. Why do I get "undefined
external" errors for some library functions?

A: Some semistandard functions have been renamed or replaced over
the years; see the full list for details.

13.25: I get errors due to library functions being undefined even
though I #include the right header files.

A: You may have to explicitly ask for the correct libraries to be
searched.

13.26: I'm still getting errors due to library functions being
undefined, even though I'm requesting the right libraries.

A: Library search order is significant; usually, you must search
the libraries last.

13.28: What does it mean when the linker says that _end is undefined?

A: You generally get that message only when other symbols are
undefined, too.


Section 14. Floating Point

14.1: When I set a float variable to 3.1, why is printf printing it as
3.0999999?

A: Most computers use base 2 for floating-point numbers, and many
fractions (including 0.1 decimal) are not exactly representable
in base 2.

14.2: Why is sqrt(144.) giving me crazy numbers?

A: Make sure that you have #included , and correctly
declared other functions returning double.

14.3: I keep getting "undefined: sin" compilation errors.

A: Make sure you're actually linking with the math library.

14.4: My floating-point calculations are acting strangely and giving
me different answers on different machines.

A: First, see question 14.2 above. If the problem isn't that
simple, see the full list for a brief explanation, or any good
programming book for a better one.

14.5: What's a good way to check for "close enough" floating-point
equality?

A: The best way is to use an accuracy threshold which is relative
to the magnitude of the numbers being compared.

14.6: How do I round numbers?

A: For positive numbers, try (int)(x + 0.5) .

14.7: Where is C's exponentiation operator?

A: Try using the pow() function.

14.8: The predefined constant M_PI seems to be missing from .

A: That constant is not standard.

14.9: How do I test for IEEE NaN and other special values?

A: There is not yet a portable way, but see the full list for
ideas.

14.11: What's a good way to implement complex numbers in C?

A: It is straightforward to define a simple structure and some
arithmetic functions to manipulate them.

14.12: I'm looking for some mathematical library code.

A: See Ajay Shah's index of free numerical software at
ftp://ftp.math.psu.edu/pub/FAQ/numcomp-free-c .

14.13: I'm having trouble with a Turbo C program which crashes and says
something like "floating point formats not linked."

A: You may have to insert a dummy call to a floating-point library
function to force loading of floating-point support.


Section 15. Variable-Length Argument Lists

15.1: I heard that you have to #include before calling
printf(). Why?

A: So that a proper prototype for printf() will be in scope.

15.2: How can %f be used for both float and double arguments in
printf()?

A: In variable-length argument lists, types char and short int are
promoted to int, and float is promoted to double.

15.3: Why don't function prototypes guard against mismatches in
printf's arguments?

A: Function prototypes do not provide any information about the
number and types of variable arguments.

15.4: How can I write a function that takes a variable number of
arguments?

A: Use the header.

15.5: How can I write a function that takes a format string and a
variable number of arguments, like printf(), and passes them to
printf() to do most of the work?

A: Use vprintf(), vfprintf(), or vsprintf().

15.6: How can I write a function analogous to scanf(), that calls
scanf() to do most of the work?

A: C9X will support vscanf().

15.7: I have a pre-ANSI compiler, without . What can I do?

A: There's an older header, , which offers about the
same functionality.

15.8: How can I discover how many arguments a function was actually
called with?

A: Any function which takes a variable number of arguments must be
able to determine *from the arguments' values* how many of them
there are.

15.9: My compiler isn't letting me declare a function that accepts
*only* variable arguments.

A: Standard C requires at least one fixed argument.

15.10: Why isn't "va_arg(argp, float)" working?

A: Because the "default argument promotions" apply in variable-
length argument lists, you should always use
va_arg(argp, double).

15.11: I can't get va_arg() to pull in an argument of type pointer-to-
function.

A: Use a typedef.

15.12: How can I write a function which takes a variable number of
arguments and passes them to some other function ?

A: In general, you cannot.

15.13: How can I call a function with an argument list built up at run
time?

A: You can't.


Section 16. Strange Problems

16.1b: I'm getting baffling syntax errors which make no sense at all,
and it seems like large chunks of my program aren't being
compiled.

A: Check for unclosed comments or mismatched preprocessing
directives.

16.1c: Why isn't my procedure call working?

A: Function calls always require parenthesized argument lists.

16.3: This program crashes before it even runs!

A: Look for very large, local arrays.
(See also questions 11.12b, 16.4, 16.5, and 18.4.)

16.4: I have a program that seems to run correctly, but then crashes
as it's exiting.

A: See the full list for ideas.

16.5: This program runs perfectly on one machine, but I get weird
results on another.

A: See the full list for a brief list of possibilities.

16.6: Why does the code "char *p = "hello, world!"; p[0] = 'H';"
crash?

A: String literals are not modifiable, except (in effect) when they
are used as array initializers.

16.8: What does "Segmentation violation" mean?

A: It generally means that your program tried to access memory it
shouldn't have, invariably as a result of stack corruption or
improper pointer use.


Section 17. Style

17.1: What's the best style for code layout in C?

A: There is no one "best style," but see the full list for a few
suggestions.

17.3: Is the code "if(!strcmp(s1, s2))" good style?

A: Not particularly.

17.4: Why do some people write if(0 == x) instead of if(x == 0)?

A: It's a trick to guard against the common error of writing
if(x = 0) .

17.5: I came across some code that puts a (void) cast before each call
to printf(). Why?

A: To suppress warnings about otherwise discarded return values.

17.8: What is "Hungarian Notation"?

A: It's a naming convention which encodes information about a
variable's type in its name.

17.9: Where can I get the "Indian Hill Style Guide" and other coding
standards?

A: See the unabridged list.

17.10: Some people say that goto's are evil and that I should never use
them. Isn't that a bit extreme?

A: Yes. Absolute rules are an imperfect approach to good
programming style.


Section 18. Tools and Resources

18.1: I'm looking for C development tools (cross-reference generators,
code beautifiers, etc.).

A: See the full list for a few names.

18.2: How can I track down these pesky malloc problems?

A: See the full list for a list of tools.

18.3: What's a free or cheap C compiler I can use?

A: See the full list for a brief catalog.

18.4: I just typed in this program, and it's acting strangely. Can
you see anything wrong with it?

A: See if you can run lint first.

18.5: How can I shut off the "warning: possible pointer alignment
problem" message which lint gives me for each call to malloc()?

A: It may be easier simply to ignore the message, perhaps in an
automated way with grep -v.

18.7: Where can I get an ANSI-compatible lint?

A: See the unabridged list for two commercial products.

18.8: Don't ANSI function prototypes render lint obsolete?

A: No. A good compiler may match most of lint's diagnostics; few
provide all.

18.9: Are there any C tutorials or other resources on the net?

A: There are several of them.

18.10: What's a good book for learning C?

A: There are far too many books on C to list here; the full list
contains a few pointers.

18.13: Where can I find the sources of the standard C libraries?

A: Several possibilites are listed in the full list.

18.13b: Is there an on-line C reference manual?

A: Two possibilities are
http://www.cs.man.ac.uk/standard_c/_index.html and
http://www.dinkumware.com/htm_cl/index.html .

18.13c: Where can I get a copy of the ANSI/ISO C Standard?

A: See question 11.2.

18.14: I need code to parse and evaluate expressions.

A: Several available packages are mentioned in the full list.

18.15: Where can I get a BNF or YACC grammar for C?

A: See the ANSI Standard, or the unabridged list.

18.15b: Does anyone have a C compiler test suite I can use?

A: See the full list for several sources.

18.15c: Where are some collections of useful code fragments and
examples?

A: See the full list for a few sources.

18.15d: I need code for performing multiple precision arithmetic.

A: See the full list for a few ideas.

18.16: Where and how can I get copies of all these freely distributable
programs?

A: See the regular postings in the comp.sources.unix and
comp.sources.misc newsgroups, or the full version of this list,
for information.


Section 19. System Dependencies

19.1: How can I read a single character from the keyboard without
waiting for the RETURN key?

A: Alas, there is no standard or portable way to do this sort of
thing in C.

19.2: How can I find out how many characters are available for
reading, or do a non-blocking read?

A: These, too, are entirely operating-system-specific.

19.3: How can I display a percentage-done indication that updates
itself in place, or show one of those "twirling baton" progress
indicators?

A: The character '\r' is a carriage return, and '\b' is a
backspace.

19.4: How can I clear the screen, or print text in color, or move the
cursor?

A: The only halfway-portable solution is the curses library.

19.5: How do I read the arrow keys? What about function keys?

A: Such things depend on the keyboard, operating system, and
library you're using.

19.6: How do I read the mouse?

A: What system are you using?

19.7: How can I do serial ("comm") port I/O?

A: It's system-dependent.

19.8: How can I direct output to the printer?

A: See the full list for ideas.

19.9: How do I send escape sequences to control a terminal or other
device?

A: By sending them. ESC is '\033' in ASCII.

19.10: How can I do graphics?

A: There is no portable way.

19.11: How can I check whether a file exists?

A: You can try the access() or stat() functions. Otherwise, the
only guaranteed and portable way is to try opening the file.

19.12: How can I find out the size of a file, prior to reading it in?

A: You might be able to get an estimate using stat() or fseek/ftell
(but see the full list for caveats).

19.12b: How can I find the modification date of a file?

A: Try stat().

19.13: How can a file be shortened in-place without completely clearing
or rewriting it?

A: There are various ways to do this, but there is no portable
solution.

19.14: How can I insert or delete a line in the middle of a file?

A: Short of rewriting the file, you probably can't.

19.15: How can I recover the file name given an open file descriptor?

A: This problem is, in general, insoluble. It is best to remember
the names of files yourself as you open them

19.16: How can I delete a file?

A: The Standard C Library function is remove().

19.16b: How do I copy files?

A: Open the source and destination files and copy a character or
block at a time, or see question 19.27.

19.17: What's wrong with the call fopen("c:\newdir\file.dat", "r")?

A: You probably need to double those backslashes.

19.18: How can I increase the allowable number of simultaneously open
files?

A: Check your system documentation.

19.20: How can I read a directory in a C program?

A: See if you can use the opendir() and readdir() functions.

19.22: How can I find out how much memory is available?

A: Your operating system may provide a routine which returns this
information.

19.23: How can I allocate arrays or structures bigger than 64K?

A: Some operating systems won't let you.

19.24: What does the error message "DGROUP exceeds 64K" mean?

A: It means that you have too much static data.

19.25: How can I access memory located at a certain address?

A: Set a pointer to the absolute address.

19.27: How can I invoke another program from within a C program?

A: Use system().

19.30: How can I invoke another program and trap its output?

A: Unix and some other systems provide a popen() function.

19.31: How can my program discover the complete pathname to the
executable from which it was invoked?

A: argv[0] may contain all or part of the pathname. You may be
able to duplicate the command language interpreter's search path
logic to locate the executable.

19.32: How can I automatically locate a program's configuration files
in the same directory as the executable?

A: It's hard; see also question 19.31 above.

19.33: How can a process change an environment variable in its caller?

A: If it's possible to do so at all, it's system dependent.

19.36: How can I read in an object file and jump to locations in it?

A: You want a dynamic linker or loader.

19.37: How can I implement a delay, or time a user's response, with sub-
second resolution?

A: Unfortunately, there is no portable way.

19.38: How can I trap or ignore keyboard interrupts like control-C?

A: Use signal().

19.39: How can I handle floating-point exceptions gracefully?

A: Take a look at matherr() and signal(SIGFPE).

19.40: How do I... Use sockets? Do networking? Write client/server
applications?

A: These questions have more to do with the networking facilities
you have available than they do with C.

19.40b: How do I... Use BIOS calls? Write ISR's? Create TSR's?

A: These are very particular to a particular system.

19.40c: I'm trying to compile a program in which "union REGS" and
int86() are undefined.

A: Those have to do with MS-DOS interrupt programming.

19.41: But I can't use all these nonstandard, system-dependent
functions, because my program has to be ANSI compatible!

A: That's an impossible requirement. Any real program requires at
least a few services which ANSI doesn't define.


Section 20. Miscellaneous

20.1: How can I return multiple values from a function?

A: Either pass pointers to several locations which the function can
fill in, or have the function return a structure containing the
desired values.

20.3: How do I access command-line arguments?

A: Via main()'s argv parameter.

20.5: How can I write data files which can be read on other machines
with different data formats?

A: The most portable solution is to use text files.

20.6: How can I call a function, given its name as a string?

A: The most straightforward thing to do is to maintain a
correspondence table of names and function pointers.

20.8: How can I implement sets or arrays of bits?

A: Use arrays of char or int, with a few macros to access the
desired bit at the proper index.

20.9: How can I determine whether a machine's byte order is big-endian
or little-endian?

A: The usual tricks involve pointers or unions.

20.10: How can I convert integers to binary or hexadecimal?

A: Internally, integers are already in binary. During I/O, you may
be able to select a base.

20.11: Can I use base-2 constants (something like 0b101010)?
Is there a printf() format for binary?

A: No, on both counts.

20.12: What is the most efficient way to count the number of bits which
are set in an integer?

A: Many "bit-fiddling" problems like this one can be sped up and
streamlined using lookup tables.

20.13: What's the best way of making my program efficient?

A: By picking good algorithms and implementing them carefully.

20.14: Are pointers really faster than arrays? How much do function
calls slow things down?

A: Precise answers to these and many similar questions depend on
the processor and compiler in use.

20.15b: People claim that optimizing compilers are good, but mine can't
even replace i/=2 with a shift.

A: Was i signed or unsigned?

20.15c: How can I swap two values without using a temporary?

A: The "clever" trick is a ^= b; b ^= a; a ^= b; see also question
3.3b.

20.17: Is there a way to switch on strings?

A: Not directly.

20.18: Is there a way to have non-constant case labels (i.e. ranges or
arbitrary expressions)?

A: No.

20.19: Are the outer parentheses in return statements really optional?

A: Yes.

20.20: Why don't C comments nest? Are they legal inside quoted
strings?

A: C comments don't nest because PL/I's comments don't either. The
character sequences /* and */ are not special within double-
quoted strings.

20.20b: What does a+++++b mean ?

A: Nothing. It's interpreted as "a ++ ++ + b", and cannot be
parsed.

20.24: Why doesn't C have nested functions?

A: They were deliberately left out of C as a simplification.

20.24b: What is assert()?

A: It is a macro which documents an assumption being made by the
programmer; it terminates the program if the assumption is
violated.

20.25: How can I call FORTRAN (C++, BASIC, Pascal, Ada, LISP) functions
from C?

A: The answer is entirely dependent on the machine and the specific
calling sequences of the various compilers in use.

20.26: Does anyone know of a program for converting Pascal or FORTRAN
to C?

A: Several freely distributable programs are available, namely
ptoc, p2c, and f2c. See the full list for details.

20.27: Can I use a C++ compiler to compile C code?

A: Not necessarily; C++ is not a strict superset of C.

20.28: I need to compare two strings for close, but not necessarily
exact, equality.

A: See the full list for ideas.

20.29: What is hashing?

A: A mapping of strings (or other data structures) to integers, for
easier searching.

20.31: How can I find the day of the week given the date?

A: Use mktime(), Zeller's congruence, or some code in the full
list.

20.32: Will 2000 be a leap year?

A: Yes.

20.34: How do you write a program which produces its own source code as
output?

A: Here's one:

char*s="char*s=%c%s%c;main(){printf(s,34,s,34);}";
main(){printf(s,34,s,34);}

20.35: What is "Duff's Device"?

A: It's a devastatingly deviously unrolled byte-copying loop. See
the full list for details.

20.36: When will the next Obfuscated C Code Contest be held?
How can I get a copy of previous winning entries?

A: See the full list, or http://www.ioccc.org/index.html .

20.37: What was the entry keyword mentioned in K&R1?

A: It was reserved to allow functions with multiple, differently-
named entry points, but it has been withdrawn.

20.38: Where does the name "C" come from, anyway?

A: C was derived from B, which was inspired by BCPL, which was a
simplification of CPL.

20.39: How do you pronounce "char"?

A: Like the English words "char," "care," or "car" (your choice).

20.39b: What do "lvalue" and "rvalue" mean?

A: An "lvalue" denotes an object that has a location; an "rvalue"
is any expression that has a value.

20.40: Where can I get extra copies of this list?