Maintaining Bit Frequency to Find OR Operation Result in a Sequence using C++

#include <bits/stdc++.h>

using namespace std;

// this function adds/subtracts every set bit of a number (OR operation)
void BitFrequency(int x, int* frequency, int add_sub) {
    for (int i = 0; i < 32; i++) {
        if (x & (1 << i)) {
            frequency[i] += add_sub;
        }
    }
}

// this function converts to decimal representation from a binary representation
int Calculate(int frequency[]) {
    int ans = 0;
    for (int i = 0; i < 32; i++) {
        if (frequency[i] >= 1) {
            ans += (1 << i);
        }
    }
    return ans;
}

int main() {
    int n;
    cin >> n;
    int a[n];
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    int frequency[32] = {0};
    for (int i = 0; i < n; i++) {
        BitFrequency(a[i], frequency, 1);
    }
    int ans = Calculate(frequency);
    cout << ans << '\n';
    return 0;
}