bits_flipped.cpp

// Find the total number of bits needed to be flipped to convert a given integer to another.
/* Input : 
x = 65(which is 01000001 in binary)
y = 80(which is 01010000 in binary)
Output : The total number of bits to be flipped is 2
 */

#include <iostream>
#include <bitset>
using namespace std;

// Find the total number of bits needed to be flipped to convert `x` to `y`
int findBits(int x, int y)
{
    // take XOR of `x` and `y` and store in `n`
    int n = x ^ y;

    // Using Brian Kernighan’s algorithm to count set bits

    // `count` stores the total bits set in `n`
    int count = 0;

    while (n)
    {
        n = n & (n - 1); // clear the least significant bit set
        count++;
    }

    return count;
}

int main()
{
    int x = 65;
    int y = 80;

    cout << x << " in binary is " << bitset<8>(x) << endl;
    cout << y << " in binary is " << bitset<8>(y) << endl;

    cout << "\nThe total number of bits to be flipped is " << findBits(x, y);

    return 0;
}