How to change the output of printf() in main() ?

Consider the following program. Change the program so that the output of printf is always 10. It is not allowed to change main(). Only fun() can be changed.

void fun()
{
    // Add something here so that the printf in main prints 10
}

int main()
{
    int i = 10;
    fun();
    i = 20;
    printf("%d", i);
    return 0;
} 

We can use Macro Arguments to change the output of printf.

#include <stdio.h>

void fun()
{
   #define printf(x, y) printf(x, 10);
}

int main()
{
    int i = 10;
    fun();
    i = 20;
    printf("%d", i);
    return 0;
} 

Output:

10

This article is contributed by Abhay Rathi. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above