# Count numbers whose difference with N is equal to XOR with N in C++

C++Server Side ProgrammingProgramming

We are a number N. The goal is to find numbers between 0 and N whose difference with N is equal to XOR with N.

We will do this by traversing no. from i=0 to i<=N and for each i, if (N-X==i^N) then increment count.

Let us understand with examples.

Input − X=6

Output − Count of numbers whose difference with N == XOR with N: 4

Explanation − Numbers are 0 2 4 6.

Input − X=20

Output − Count of numbers whose difference with N == XOR with N: 4

Explanation − Numbers are 0 4 16 20

## Approach used in the below program is as follows

• We take integer N.

• Function diffisXOR(int n) takes n and returns a count of numbers whose difference with n is equal to xor with n.

• Take the initial count as 0.

• Traverse from i=0 to i<=n.

• If i-n==i^n. Increment count

• At the end of for loop count will have the desired result.

• Return count and print.

## Example

#include <bits/stdc++.h>
#include <math.h>
using namespace std;
int diffisXOR(int n){
int count = 0;
for (int i = 0; i <= x; i++){
if((x-i)==(i^x))
{ count++; }
}
return count;
}
int main(){
int N = 15;
int nums=diffisXOR(N);
cout <<endl<<"Count of numbers whose difference with N == XOR with N: "<<nums;
return 0;
}

## Output

If we run the above code it will generate the following output −

Count of numbers whose difference with N == XOR with N: 16