Open In App
Related Articles

Anything written in sizeof() is never executed in C

Improve Article
Save Article
Like Article

In C/C++ sizeof() operator is used to find size of a date type or variable. Expressions written in sizeof() are never executed.


// C program to demonstrate that the
// expressions written in sizeof() are
// never executed
#include <stdio.h>
int main(){
    // The printf in sizeof is not executed
    // Only the return type of printf is 
    // considered and its size is evaluated
    // by sizeof,
    int a = sizeof(printf("hey"));
    printf("%d", a);
    return 0;


Even if we assign a value inside sizeof(), the changes are not reflected.

// One more C program to demonstrate that 
// the expressions written in sizeof() are
// never executed
#include <stdio.h>
int main() {
    int a = 5;
    int b = sizeof(a = 6);
    printf("a = %d,  b = %d\n", a, b);
    return 0;

a = 5, b = 4

If you like GeeksforGeeks and would like to contribute, you can also write an article using or mail your article to See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.

Whether you're preparing for your first job interview or aiming to upskill in this ever-evolving tech landscape, GeeksforGeeks Courses are your key to success. We provide top-quality content at affordable prices, all geared towards accelerating your growth in a time-bound manner. Join the millions we've already empowered, and we're here to do the same for you. Don't miss out - check it out now!

Last Updated : 02 Oct, 2017
Like Article
Save Article
Similar Reads