哪错了

#include <bits/stdc++.h>

using namespace std;
int main() {
    freopen("prime.in", "r", stdin);
    freopen("prime.out", "w", stdout);
    int n;
    cin >> n;
    for (int i = 2; i <= n; i++) {
        if (n == 0) {
            cout << n << " is a prime number.";
        } else if (n % i == 0) {
            cout << n << " is not a prime number.";
            return 0;
        } else if (n % i != 0) {
            cout << n << " is a prime number.";
            break;
        }
    }
    fclose(stdin);
    fclose(stdout);
    return 0;
}