count3.cpp

#include "argparse.hpp"
#include <iostream>

auto main(int argc, char * argv[]) -> int
{
    try
    {
        auto parser = argparse::ArgumentParser();
        parser.add_argument("square").help("display a square of a given number").type<int>();
        parser.add_argument("-v", "--verbosity").help("increase output verbosity").action(argparse::count);
        auto parsed = parser.parse_args(argc, argv);
        auto value = parsed.get_value<int>("square");
        auto answer = value * value;
        auto verbosity = parsed.get_value<int>("verbosity");
        if (verbosity >= 2)
        {
            std::cout << "the square of " << value << " equals " << answer << '\n';
        }
        else if (verbosity >= 1)
        {
            std::cout << value << "^2 == " << answer << '\n';
        }
        else
        {
            std::cout << answer << '\n';
        }
    }
    catch (argparse::type_error const & e)
    {
        std::cout << "error: " << e.what() << '\n';
    }
}