30. Count Set Bits in an Integer

#include <stdio.h>

int countSetBits(unsigned int n) {
    // Write your code here
    int totbits = sizeof(n)*8, count=0,mask=1;
    while(totbits!=0)
    {
        if(n&mask)
        count++;
        mask<<=1;
        totbits--;
    }
    return count;
}

int main() {
    int n;
    scanf("%d", &n);
    printf("%d", countSetBits(n));
    return 0;
}