Count number of bits to be flipped to convert A to B

You are given 2 integers A and B.

You need to findout the number of bits to be flipped to convert A to B.

Input : a = 10, b = 20

Output : 4

Binary representation of a is 00001010

Binary representation of b is 00010100

a XOR b =00011110

The number of set bits are 4.

Solution is very simple.

We need to XOR the elements.

Then count the number of set bits to arrive at the solution.

#include <vector>    
#include <algorithm>  
//visit www.ProDeveloperTutorial.com for 450+ solved questions  
#include <iostream>    
#include <string>
#include <unordered_set>
#include <queue>

using namespace std;

int count_set_bits(int n) 
{ 
    int count = 0; 

    while (n > 0) 
    { 
        count++; 
        n &= (n-1); 
    } 
    return count; 
} 
  
int count_bits_to_be_flipped(int a, int b) 
{ 
    int temp = a^b;
    return count_set_bits(temp); 
} 
  
int main() 
{ 
    int a = 10; 
    int b = 20; 
    cout << "The number of set bits are : "<< count_bits_to_be_flipped(a, b)<<endl; 
    return 0; 
} 

Output:

The number of set bits are : 4