Find XOR of two number without using XOR operator

2.7

Given two integers, find XOR of them without using XOR operator, i.e., without using ^ in C/C++.

Examples:

Input:  x = 1, y = 2
Output: 3

Input:  x = 3, y = 5
Output: 6

A Simple Solution is to traverse all bits one by one. For every pair of bits, check if both are same, set the corresponding bit as 0 in output, otherwise set as 1.

// C++ program to find XOR without using ^
#include <iostream>
using namespace std;

// Returns XOR of x and y
int myXOR(int x, int y)
{
    int res = 0; // Initialize result
    
    // Assuming 32-bit Integer 
    for (int i = 31; i >= 0; i--)                     
    {
       // Find current bits in x and y
       bool b1 = x & (1 << i);
       bool b2 = y & (1 << i);
       
        // If both are 1 then 0 else xor is same as OR
        bool xoredBit = (b1 & b2) ? 0 : (b1 | b2);          

        // Update result
        res <<= 1;
        res |= xoredBit;
    }
    return res;
}

// Driver program to test above function
int main()
{
   int x = 3, y = 5;
   cout << "XOR is " << myXOR(x, y);
   return 0; 
}

Output:

XOR is 6

Thanks to Utkarsh Trivedi for suggesting this solution.

 

A Better Solution can find XOR without using loop.

1) Find bitwise OR of x and y (Result has set bits where either x has set or y has set bit). OR of x = 3 (011) and y = 5 (101) is 7 (111)

2) To remove extra set bits find places where both x and y have set bits. The value of expression “~x | ~y” has 0 bits wherever x and y both have set bits.

3) bitwise AND of “(x | y)” and “~x | ~y” produces the required result.

Below is C++ implementation.

// C++ program to find XOR without using ^
#include <iostream>
using namespace std;

// Returns XOR of x and y
int myXOR(int x, int y)
{
   return (x | y) & (~x | ~y);
}

// Driver program to test above function
int main()
{
   int x = 3, y = 5;
   cout << "XOR is " << myXOR(x, y);
   return 0; 
}

Output:

XOR is 6

Thanks to jitu_the_best for suggesting this solution.

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