command line argument help

[bobnet]

I've read the command line tutorial and I under stand it, but whats the "standard" process to accept arugments with switches ?

eg
PROGRAM: myApp
OPTIONS: -a somethingA
-b somethingB
-c somethingC

how do I go about acception

myApp -a somethingA -b somethingB
or
myApp -b somethingB -a somethingA

ie in different orders?

[Cat]

I would just iterate through them. Here's a quick example I cooked up:

#include <iostream>
#include <string>

int parseParams(int count, char * arg[]);

#define PARSE_SUCCESS    0
#define PARSE_TOOFEW    -1
#define PARSE_BADSWITCH -2

int main(int argc, char * argv[])
{
	int i = parseParams(argc-1, argv + 1);
	if (i == PARSE_SUCCESS) std::cout << "Parse Success" << std::endl;
	if (i == PARSE_TOOFEW) std::cout << "Too Few Parameters" << std::endl;
	if (i == PARSE_BADSWITCH) std::cout << "Unknown Switch" << std::endl;
}

int parseParams(int count, char * arg[]){
	
	std::string sSwitch;
	int c = 0;

	while(true){
		if (count - c < 1) return PARSE_SUCCESS; // We're out of parameters
		sSwitch = arg[c];
		c++;

		if (sSwitch == "-a"){
			if (count - c < 2) return PARSE_TOOFEW;
			std::cout << "Switch A: " << arg[c] << ", " << arg[c+1] << std::endl;
			c += 2;
		}
		else if (sSwitch == "-z"){
			std::cout << "Switch Z" << std::endl;
		}
		else if (sSwitch == "-m"){
			if (count - c < 1) return PARSE_TOOFEW;
			std::cout << "Switch M:" << arg[c] << std::endl;
			c++;
		}
		else return PARSE_BADSWITCH;
	}
}

Here, c is the number of parameters we've parsed (so count - c is the number left to parse).

We use argc -1, argv + 1 because we don't want to parse the first entry of argv (which is the executable name).

Sample output:

C:\>test -m 4 -a "Hello there" "My friend" -z
Switch M:4
Switch A: Hello there, My friend
Switch Z
Parse Success