Question

#include "stdio.h"
#include "conio.h"

int main(void)
{

        if(printf("ABC"))
        {

        }
        else
        {
            printf("XYZ");
        }
        _getch();
        return 0;
}

output : ABC

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

#include "stdio.h"
#include "conio.h"

int main(void)
{

        if(puts("ABC"))
        {

        }
        else
        {
            printf("XYZ");
        }
        _getch();
        return 0;
}

output : ABC XYZ 

(IDE : MSVC++)
what is the difference between printf and puts in if statement in above 2 programs??

Answer 1

• printf returns the number of character written
• puts returns a non-negative value in case of success

As a result :

• In the first code, printf returns a positive value which evaluates to true, the else branch is never executed, thus printing ABC only
• In the second code, puts most likely succeeds and returns 0 which evaluates to false, the else branch gets executed, thus printing both ABC and XYZ

As pointed out by others, puts will also append a newline while printf won’t.