Examples

Full text of example from tutorial

#include <iostream>
#include "ArgParse/argparse.h"

int main(int argc, char** argv)
{
    auto parser = argparse::ArgumentParser("Program name").SetDescription("Description of program");
    parser.AddArgument(argparse::CreateNamedArgument()
        .SetLongName("numbers")
        .SetAnyNumberOfArgumentsButAtleastOne()
        .SetType(argparse::ArgTypeCast::e_int));
    parser.AddArgument(argparse::CreateNamedArgument()
        .SetLongName("some_boring_long_name")
        .SetAnyNumberOfArgumentsButAtleastOne()
        .SetType(argparse::ArgTypeCast::e_int)
        .SetHelp("some_boring_long_name description with some important information for user.")
        .SetRequired(false));

    auto obj = parser.ParseArgs(argc, argv);
    if (obj.IsArgValid())
    {
        auto arg = obj.GetArg("numbers");
        if (arg.GetArgumentExists())
        {
            for (auto& el : arg.GetAsVecInt())
            {
                std::cout << el << std::endl;
            }
        }
    }
    else
    {
        std::string help = parser.GetHelp(80);
        std::cout << obj.GetErrorString() << std::endl;
        std::cout << help << std::endl;
    }

    return 0;
}

This exmaple will create program with keys -n, --number, -s, --some_boring_long_name, -h and --help. Help will be autogenerated. The types of numbers and some_boring_long_name are integers with count from 1 to infinite.

Typical output without any arguments:

main.cpp [-n,--numbers [n ...] ] [-s,--some_boring_long_name [s ...] ] -h,--help
Description of program

optional arguments:

-n,--numbers            some numbers description with some important information
                        for user. Type: INT. Args count: at least one.
-s,--some_boring_long_name
                        some_boring_long_name description with some important information
                        for user. Type: INT. Args count: at least one.
-h,--help               Show help!

Note actually terminal cannot get infinite numbers of arguments. In most cases maximum length of all input that terminal can pass is limited with 8 kb.

Full text of example from tutorial but shorter way

#include <iostream>
#include "ArgParse/argparse.h"

int main(int argc, char** argv)
{
    auto parser = argparse::ArgumentParser(__FILE__).SetDescription("Description of program");

    parser.AddArgument(argparse::CreateNamedArgument("n", "numbers", argparse::kFromOneToInfinteArgCount,
        argparse::ArgTypeCast::e_int, false, 
        "some numbers description with some important information for user."));
    parser.AddArgument(argparse::CreateNamedArgument("s", "some_boring_long_name", argparse::kFromOneToInfinteArgCount,
        argparse::ArgTypeCast::e_int, false, 
        "some_boring_long_name description with some important information for user."));
    auto obj = parser.ParseArgs(argc, argv);
    if (obj.IsArgValid())
    {
        auto arg = obj.GetArg("numbers");
        if (arg.GetArgumentExists())
        {
            for (auto& el : arg.GetAsVecInt())
            {
                std::cout << el << std::endl;
            }
        }
    }
    else
    {
        std::string help = parser.GetHelp(80);
        std::cout << obj.GetErrorString() << std::endl;
        std::cout << help << std::endl;
    }

    return 0;
}

Making 1 required argument, with 1 required value

generic -h, --help is suppressed example compiles for c++17 and uses std::any approach

#include <iostream>
#include "ArgParse/argparse.h"

int main(int argc, char** argv)
{
    auto parser = argparse::ArgumentParser("main").SetDescription("ArgParse example");

    parser.AddArgument(argparse::CreateNamedArgument("b", "b_key", 1,  argparse::ArgTypeCast::e_int, true, 
        R"=(some "b_key" description with some important information for user)="));

    parser.SetAddHelp(false);

    auto obj = parser.ParseArgs(argc, argv);
    if (obj.IsArgValid())
    {
        auto arg = obj.GetArg("b_key");
        std::cout << arg.Get().type().name() << ": " << std::any_cast<int>(arg.Get()) << std::endl;
    }
    else
    {
        std::string help = parser.GetHelp(80);
        std::cout << obj.GetErrorString() << std::endl;
        std::cout << help << std::endl;
    }

    return 0;
}

You can change 1 to 0 from this example. It will be flag, and you cannot access to it's content.

Adding positional argument

Positional argument should be inputted as raw argument without any key. This is only difference between keyed and positional arguments.

#include <iostream>
#include "ArgParse/argparse.h"

int main(int argc, char** argv)
{
    auto parser = argparse::ArgumentParser("main").SetDescription("ArgParse example");

    parser.AddArgument(argparse::CreatePositionalArgument("int1").SetType(argparse::ArgTypeCast::e_int).SetRequired(false));

    auto obj = parser.ParseArgs(argc, argv);
    if (obj.IsArgValid())
    {
        auto arg = obj.GetArg("int1");
        if (arg.GetArgumentExists())
        {
            std::cout << arg.Get().type().name() << ": " << std::any_cast<int>(arg.Get()) << std::endl;
        }
    }
    else
    {
        std::string help = parser.GetHelp(80);
        std::cout << obj.GetErrorString() << std::endl;
        std::cout << help << std::endl;
    }

    return 0;
}