#include <iostream>
#include <vector>

auto main() -> int
{
    std::cout << "Enter -1 to quit\n";
    std::vector<int> items { 97, 84, 72, 65 };
    std::cout << "Enter an index: ";
    for (int print_index; std::cin >> print_index;) {
        if (print_index == -1)
            break;
        std::cout << items.at(static_cast<unsigned int>(print_index)) << '\n';
        std::cout << "Enter an index: ";
    }
}