arguments [Clemens Wacha]

Overview

Arguments is a very simple and intuitive command line arguments parser written in C++ that takes (argc, argv) as arguments and then lets you easily test for given command line options. Have a look at the example code to see how easy it is.

This class makes handling argc, argv (as supplied by main() i.e.) very easy. After initializing you provide it with an option you would like to have and an optional default value. If the option is found inside argv it will be returned to you, if not you get the default value. Reading an option from the argument list removes it from the argument list. It works like a stack with a find-and-pop function.

Instead of using argc, argv you can also supply a vector of strings. This comes in handy if you have a line that was splitted into tokens by split_line for example.

Features

short options
long options
flags
internal storage realised as STL vector
-flag --long-option-flag
-option 5 --long-option-text 5

Remarks

you cannot unset a flag with something like -flag 0. You will have to test for another flag i.e. -notflag.
-option=5 will not be recognized. There is no internal splitter.
every option takes exactly 1 argument.

Download

Code Example

#include "Arguments.h"
 
#include <string>
#include <iostream>
 
using namespace std;
 
int main(int argc, char* argv[]) {
 
	// First, we need to initalize a new Arguments object
	Arguments a(argc, argv);
 
	// now you just provide the options you would like to have
	string this_binary = a.front();
 
	// !! remark that you can provide an option MORE THAN ONE time and you
	// !! will get subsequent options. A found option will be removed from the
	// !! argument list !!
 
	// Format: get(option to search, default value, long option to search);
	//  long_option is optional
	int my_int = a.get("-a", 0);
	double my_int2 = a.get<double>("-a", 340, "--with-long-option");
	string test = a.get<string>("-test", "not here");
	bool show_help = a.getFlag("-h", "--help");
 
	// if you are interested a supplied filename you can use front()
	//  or back() to pop the first or last element
	string filename = a.back();
 
	// now we check if we have popped all options of if there are some left (i.e. the user entered an option
	// that does not exist)
	if( a.size() > 0 ) {
		cout << "Unsupported option(s) given: " << a.list() << endl;
	}
 
	if( show_help || a.size() > 0 || filename == "") {
		cout << "usage: " << this_binary << " -a -h filename" << endl;
	}
 
	//now do your stuff
 
	cout << "a=" << my_int << " other a=" << my_int2 << " test=" << test << endl;
 
	return 0;
}

Documentation

Only relevant members are shown!

class Arguments {
 
public:
	Arguments();
	Arguments(int argc, char* argv[]);
	Arguments(const std::vector<std::string>&);
	~Arguments();
 
	// returns true if flag is found, false else
	bool getFlag(const std::string& option, const std::string& long_option = "");
	// returns type T if found or default_value (converted to type T) else
	// Remark: does NOT work with char*. Use string instead and c_str() to get a char*
	template<typename T> T get(const std::string& option, const T& default_value, const std::string& long_option = "");
 
	// return first element
	std::string front();
	// return last element
	std::string back();
	// return number of elements currently in the argument list
	unsigned int size();
	// return comma separated string containing all elements in the argument list
	std::string list();
};

License

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Commandline Argument Parser