/******************************************************************************
 * This program masks all but the last four digits if a credit card number.
 * 
 * Copyright © 2021 Richard Lesh.  All rights reserved.
 *****************************************************************************/

#include "Utils.hpp"
#include <iostream>
#include <regex>
#include <string>
#include <vector>

using namespace std;

static const vector<string> testCases = {"1234 5678 9012 3456", "4893 8573 0203 1929", "6992 2839 4929 3902"};

string maskCreditCard(string cardNumber) noexcept {
    return std::regex_replace(cardNumber, regex("\\d{4,4} "), "XXXX ");
}

int main(int argc, char **argv) {
    for (auto s : testCases) {
        cout << maskCreditCard(s) << endl;
    }
    return 0;
}