30. Count Set Bits in an Integer

#include <stdio.h>

int countSetBits(unsigned int n) {
    int i,a;
    int countSetBits = 0;
    for( i = 0; i < 32; i++ ){
        a = ( 1<<i ) & n;
        if( a ) 
        {
         countSetBits++;
        }
    }
    return countSetBits;
}

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