Complement of Base 10 Integer

Every non-negative integer N has a binary representation.  For example, 5 can be represented as "101" in binary, 11 as "1011" in binary, and so on.  Note that except for N = 0, there are no leading zeroes in any binary representation.

The complement of a binary representation is the number in binary you get when changing every 1 to a 0 and 0 to a 1.  For example, the complement of "101" in binary is "010" in binary.

For a given number N in base-10, return the complement of its binary representation as a base-10 integer.

Example:

Input: 5
Output: 2
Explanation: 5 is "101" in binary, with complement "010" in binary, which is 2 in base-10.

Approach:

C++

#include <bits/stdc++.h>
using namespace std;

int bitwiseComplement(int N)
{
    if (N == 0)
        return 1;
    vector<int> arr;
    while (N > 0)
    {
        if (N % 2 == 0)
            arr.push_back(1);
        else
            arr.push_back(0);
        N = N / 2;
    }
    int res = 0;
    for (int i = 0; i < arr.size(); i++)
    {
        res += arr[i] * pow(2, i);
    }
    return res;
}
int main()
{
    int n = 5;

    cout << bitwiseComplement(n);
    return 0;
}