Q1:

What will be the output of the program?

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

printf() returns the number of charecters printed on the console. Step 1: if(ch = printf('')) here printf() does not print anything, so it returns '0'(zero).
Step 2: if(ch = 0) here variable ch has the value '0'(zero).
Step 3: if(0) Hence the if condition is not satisfied. So it prints the else statements.
Hence the output is 'It doesn't matters'. Note: Compiler shows a warning 'possibly incorrect assinment'.