DZone Snippets: arguments code

Simple way to check command line arguments in a C program

jmftrindade (Joana M. F. da Trindade) — Mon, 25 Feb 2008 22:49:18 GMT

A simple way to check command line arguments.

Author: Joana Matos Fonseca da Trindade
Date: 2008.02.25



#include 

#include 

#include 



/* minimum required number of parameters */

#define MIN_REQUIRED 2



/* display usage */

int help() {

   printf("Usage: myprogram [-s ] [-n ] [-true]\n");

   printf("\t-s: a string a\n");

   printf("\t-n: a number\n");

   printf("\t-true: a single parameter\n");



   return 1;

}



/* main */

int main(int argc, char *argv[]) {

   if (argc < MIN_REQUIRED) {

      return help();

   }

   int i;



   /* iterate over all arguments */

   for (i = 1; i < (argc - 1); i++) {

       if (strcmp("-s", argv[i]) == 0) {

          /* do something with it */ 

          printf("string = %s\n", argv[++i]);

          continue;

       }

       if (strcmp("-n", argv[i]) == 0) {

          /* do something with it. for example, convert it to an integer */

          printf("number = %i\n", atoi(argv[++i]));

          continue;

       }

       if (strcmp("-true", argv[i]) == 0) {

          printf("true activated\n");

          continue;

       }

       return help();

   }

   return 0;

}

basic batch conditional evaluation

thefamousnomo (Robin) — Wed, 13 Jun 2007 15:42:22 GMT

// check if argument has been passed to batch file



if not [%1]==[] echo %1

if not [%1]'==' echo %1

Python keyword arguments

snifty (Pat Hall) — Thu, 31 Aug 2006 00:21:17 GMT

This is something I always forget how to do, and it's kind of hard to Google or search the Python docs because you can't search for **.

The point is, when using **kwargs, you have to use the ** prefix not only in the function definition, but also in the call, prefixed to the variable you want to use as a keyword dictionary.



>>> d = dict(zip(list('123'),list('abc')))

>>> d

{'1': 'a', '3': 'c', '2': 'b'}

>>> def printkwargs(**kwargs):

...  for k,v in kwargs.items(): print k,v

...

>>> printkwargs(**d)

1 a

3 c

2 b

>>> printkwargs(d)

Traceback (most recent call last):

  File "", line 1, in ?

TypeError: printkwargs() takes exactly 0 arguments (1 given)



>>> # you have to tell python that you want the argument to be treated as a keyword dictionary by prefixing it with **

>>> # more info at http://mail.python.org/pipermail/python-list/2006-March/332182.html