efficient way of counting number of set bits in a number

/* In GCC, we can directly count set bits using __builtin_popcount(). So we can avoid a separate function for counting set bits. cout << __builtin_popcount (4) << endl; 1 Initialize count: = 0 2 If integer n is not zero (a) Do bitwise & with (n-1) and assign the value back to n n: = n&(n-1) (b) Increment count by 1 (c) go to step 2 3 Else return count link : https://www.geeksforgeeks.org/count-set-bits-in-an-integer/ */ unsigned int countSetBits(int n) { unsigned int count = 0; while (n) { n &= (n-1) ; count++; } return count; }