What is the different between while(0) and while(1) in c language

[abhishek maheshwari]

Hiiii,
i am looking for answer of this question, please give the answer with example.
What is the different between while(0) and while(1) in c language?

 

[dg32768]

The word while() in C occurs in two different constructs: in a while-loop

while (condition)
    loop-body;

and in a do-loop:

do
    loop-body;
while (condition);

In a while-loop, the condition is tested, and if true (non-zero) the body is executed; and then the test is repeated, and the body repeated, until the test is false (0). So

while (1)
{
    body;
}

will result in the body of the loop being executed forever (or until loop exit is triggered some other way, such as break or return). Whereas

while (0)
{
    body;
}

will mean that the body is not executed at all -- obviously this is not very useful!

In a do-loop, the body is executed first, and then the test is evaluated, and the whole is repeated until the test is false. So

do
{
    body;
} while (1);

will also result in the body being repeated forever (or until a break/return is reached), whereas

do
{
    body;
} while (0);

means the body will be executed just once. This is most commonly used in macro definitions, to prevent confusion between code generated by the macro and code immediately after the macro call { but that's a separate question }.

 

[atindra kumar nath]

While(1) is a infinite loop so if you need to come out of it then you need to issue the break statement explicitly.

main()
{
  int i=0;
  while(1)
  {
    printf("%d\n", i++);
    if (i==2)
      break;
  }
}

While(0) means non entry and code under while will never get executed.

main()
{
int i=0;
while(0)
{
printf("%d\n", i++); // This will never get executed
if (i==2)
break;
}
}

Source:- http://tech.queryhome.com/48201/wha...e-0-and-while-in-c-language?show=48208#a48208

 

[Vishal Jamdagni]

Hey there,
In C unlike languages like java where the Boolean values can be only either "true" or "false", they can be a bit different where a "non-zero" digit like "1" would be treated as "true" and as you might have guessed a "zero" would be treated as a "false"
So, a while(1){ } would mean the loop would iterate infinitely and a while(0){ } would mean that the body of the loop will never get executed.

 

[shaili shah]

loops work based on true(1) and false(0) condition.
while(condition)
if condition is true then statement inside while is executed,else it is avoided. condition will be false only if value will be zero and for rest other values it will be true.
so for
i) while(0)
{
//statement
}
it is evaluated as false and hence statement inside while won't be executed.
ii) while(1){
//statement
}
in this condition is true(1) so it will execute statement inside while loop infinite times as it will will evaluate true always.