5. Count Set Bits in an Integer

#include <stdio.h>
int countSetBits(unsigned int n) {
   int count = 0;
   while (n) {
       count += n & 1;
       n >>= 1;
   }
   return count;
}
int main() {
   int n;
   scanf("%d", &n);
   printf("%d\n", countSetBits(n));
   return 0;
}

Explanation:

• We check the least significant bit (LSB) using n & 1.
• Shift n right by 1 (n >>= 1) to process the next bit.
• Repeat until n becomes 0.
• If N is negative, its 2’s complement representation will be used, so consider handling it accordingly.