#include <stdio.h>

int main(void)
{
    unsigned long int number, num1, num2, mask;
    int i;
    char str[33];
   
    printf("Please input num1 and num2 : ");
    scanf("%lu %lu", &num1, &num2);
   
    /*********Found************/
    mask = __________________;
    number = num1 ^ num2;
    for(i=0; i<32; i++)
    {
        /*********Found************/
        str[i] = __________________;
        mask >>= 1;
    }
    str[32] = '\0';
    printf("%lu ^ %lu = %s\n", num1, num2, str);
   
    return 0;
}   

不大明白，这题怎么做？