Question

THIS PROGRAM HAS TO BE WRITTEN IN C

single function to count the number of leading zeroes in the 32-bit input argument passed to the function (leading zeroes are the zeroes that occur in the most significant bit positions of the number until a bit value of ‘1’ is found).

Answer 1

#include <stdio.h>

int count_leading_zeros(unsigned int n) {
    int count = 0, c = 0;
    while (n > 0) {
        ++c;
        if (n % 2 == 1) {
            count = c;
        }
        n /= 2;
    }
    return 32-count;
}

int main() {
    unsigned int n = 0xFF;
    printf("Number of leading zeros in 0x%x is %d\n", n, count_leading_zeros(n));
    n = 0xF0000000;
    printf("Number of leading zeros in 0x%x is %d\n", n, count_leading_zeros(n));
    n = 0x00F0F0A3;
    printf("Number of leading zeros in 0x%x is %d\n", n, count_leading_zeros(n));
    return 0;
}