arg_ex1.cc

A more complex example with help text

#include <arg.hh>
#include <iostream>
using namespace std;
string const version = "1.0";
 
int main(int argc, char ** argv)
{
    // system parameters
    // setup parser
    arg::Parser parser;
    parser.set_header("arg Testing Program v" + version);
    parser.add_help("");
    parser.add_help("available options are:");
    int n;
    parser.add_opt('n', "number").stow(n = 10)
        .help("set number of nodes to INT", "INT")
        .show_default();
    string f;
    int f_given = 0;
    parser.add_opt('i', "input").stow(f)
        .help("read data from FILE", "FILE")
        .set(& f_given).once();
    parser.add_opt_help();
    parser.add_opt_version(version);
    // parse command line
    try {
        parser.parse(argc, argv);
    }
    catch (arg::Error e) {
        cout << "Error parsing command line: " << e.get_msg() << '\n';
        return 1;
    }
    // check for parameter consistency
    if (! f.size()) {
        cout << "Need to specify the input file!\n";
        return 1;
    }
    // output
    cout << "The parameters are:\n"
          << "number = " << n << '\n'
          << "input = " << f << '\n';
    return 0;
}