C Programming - Control Instructions - Discussion

Here, printf() is a function that is used to evaluate the condition in if statement. We need to check whether printf() is printing anything.

If yes, then the If statement will evaluate to true. If it does not print anything then the if statement evaluate to false.

In this program printf() function doesn't print anything, so the condition is false and hence the result "It doesn't matters". Also the variable being char or integer doesn't matter.

#include<stdio.h>
int main()
{
char ch;
if(ch = printf("Hai"))
printf("\nIt matters\n");
else
printf("It doesn't matters\n");
return 0;
}

It is executed and prints "Hai" follows "It matters", character datatype assigns only one character as well as if condition checking only for '==' how will works?.

Mr. Sushant how can a if statement check the condition without == symbol.According to u ...U said that we are simply executing the program..But it is wrng bcoz if the 'if' statement comaparison is wrong then it goes to the 'else' statement, but here there is no comparison takes place. So how can u tell the out put is the statement in the else statement.....?????? ..Ganesh

if(ch = printf ("")) , here printf("") will give 0 output and then 0 is assigned to variable ch {ch=0}, but we can't assign int value to char variable directly, for this we need explicit typecasting. So this expression ch=0; is false So condition inside if become false and thus the result.

Hai @all.
we can write == in the if condition. Bhaskar is asking what if we write == in that place.
Then it compares 0 with value in ch, since ch is a garbage value, 99.999999% times we will get else output. In condition ch is zero randomly we will get if statement executed. :)

@Bhaskar,

Yes you do comparisons by "==", however we are not making a comparison over here. We are simple executing a statement in the if() statement and the output decides the condition to be true ie the result is 0(means false) or the result is >1 (means true)

if(ch=printf(""))
printf("matters");
else
printf("it does not matters");

The above snippet will not execute in Turbo C, it will show error IF statement, its incorrect statement.

Error: "possibly in correct statement".

When I use:

#include<stdio.h>
int main()
{
char ch;
if(ch == printf(""))
printf("It matters\n");
else
printf("It doesn't matters\n");
return 0;
}

Why does it print it matters?

Hello. Here in the if condition ch=0, means we are assigning a value to ch, so it will return 1 and should execute if condition. Please do clear my doubt if I am wrong.

printf always return no of character.

Do that you can understand better.

printf("%d",printf("%d",printf("Hi how are you"))).