args.hpp

single-header argument parser for C++17

copy args.hpp into your project, done. no cmake, no install.

#include "args.hpp"

int main(int argc, char** argv) {
    args::Parser p("mytool", "does a thing");
    p.flag("verbose", "print more stuff");
    p.option("output", "output file", "out.txt");
    p.option("count", "how many", "1");
    p.positional("input", "input file");

    try {
        p.parse(argc, argv);
    } catch (const args::ParseError& e) {
        std::cerr << e.what() << "\n";
        return 1;
    }

    if (p.get_flag("verbose"))
        std::cout << "verbose mode\n";

    std::string outfile = p.get("output");
    int n = p.get_as<int>("count");
    std::string infile = p.get("input");
}

running ./mytool --help gives you:

Usage: mytool <input> [options]
does a thing

Options:
  -h, --help       show this message
  --verbose        print more stuff
  --output <val>   output file (default: out.txt)
  --count <val>    how many (default: 1)

Positional arguments:
  input            input file [required]

API:

p.flag(name, help) — boolean, present or not
p.option(name, help, default, required) — takes a value
p.positional(name, help, required) — positional arg
p.parse(argc, argv) — throws ParseError on bad input
p.get(name) — returns string value
p.get_as<T>(name) — returns T via >> conversion
p.get_flag(name) — returns bool
p.has(name) — was it actually provided

supports --key=value syntax, short flags (-v), and --help is built in.

License: MIT