Managing argc and argv[] with STL in a simple way

• Download source files - 14 Kb

Introduction

This class unifies the process to read the argument list of your main() in a very easy way. It provides many features to support options with parameters, optional parameters and automatic output of error messages and a short manual. It uses STL and is unicode compliant.

A short piece of HTML documentation, the source, a .DSP for a static library and a a test application is given in Arguments_src.zip.

The following code should be enough to make you curious:

After including...

#include "Arguments.h"

...you build an instance of Arguments in your main(); the name of the application, a copyright notice and the possible option-markers are given as parameters to the constructor...

void main( int argc, char *argv[] )
{
	Arguments cArg( "argtest", "(C) 2001 NOVACOM GmbH", "-/" );

Now you add the definition of your options and parameters. The first example is a simple option "-h" to get the manual. For that you can use the AddOption() with the character 'h' and a brief description that occurs automatically in the manual.

	cArg.AddOption('h', "display usage help");

The second one is the parameter "2". It's definition is a little bit more complicated, because we now want to add a parameter to the option. Building the instance of cOpt is similar to the AddOption call. When you create the option in this way you are able to add parameters with AddArgument() to the !option!:

	Arguments::Option	cOpt( '2', "define additional input file" );
	cOpt.AddArgument( "outfile2", "additional input filename" );
	cArg.AddOption( cOpt );

Adding arguments is quite simple too. You use AddArgument() to define an argument with a name and a brief description.

	cArg.AddArgument( "infile", "filename to read" );

You are also able to give a default value for an argument. The result is an optional argument...

	cArg.AddArgument( "outfile", "filename for output", "stdout" );

After defining the options and arguments you can instruct your Arguments instance to parse the command line with...

	if( !cArg.Parse( argc, argv ) )
		exit(-1);

To request an option (e.g. the -h option) you only have to write the following code...

	if( cArg['h'] )
	{
		cArg.Usage();
		exit(0);
	}

It's the same with '-2', and you also get the argument of this option by using []...

	if( cArg['2'] )
		cout << "Option -2 set, outfile2 = " << cArg['2']["outfile2"] << endl;
	else
		cout << "Option -2 not set" << endl;

Requesting the arguments doesn't really differ...

	cout << "infile = " << cArg["infile"] << endl;

So the manual output of our example will be...

       Usage: argtest [-2 outfile2] [-h] infile [outfile]

       Options:
             -2        define additional input file
              outfile2       = additional input filename
             -h        display usage help

       Arguments:
             infile  = filename to read
             outfile = filename for output
                    optional argument (default='stdout')

       (C) 2001 NOVACOM GmbH

Isn't it easy to change the settings of your program arguments, now?