Q1:

What will be the output of the program?

#include<stdio.h>
int main()
{
    unsigned int i = 65535; /* Assume 2 byte integer*/
    while(i++ != 0)
        printf('%d',++i);
    printf('\n');
    return 0;
}

Here unsigned int size is 2 bytes. It varies from 0,1,2,3, ... to 65535. Step 1:unsigned int i = 65535; Step 2:
Loop 1: while(i++ != 0) this statement becomes while(65535 != 0). Hence the while(TRUE) condition is satisfied. Then the printf('%d', ++i); prints '1'(variable 'i' is already incremented by '1' in while statement and now incremented by '1' in printf statement) Loop 2: while(i++ != 0) this statement becomes while(1 != 0). Hence the while(TRUE) condition is satisfied. Then the printf('%d', ++i); prints '3'(variable 'i' is already incremented by '1' in while statement and now incremented by '1' in printf statement)
....
....
The while loop will never stops executing, because variable i will never become '0'(zero). Hence it is an 'Infinite loop'.