How to store argv[x] in my program??? Post: 302582862

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Top Forums Programming How to store argv[x] in my program??? Post 302582862 by jim mcnamara on Sunday 18th of December 2011 11:23:14 PM

12-19-2011

Registered User

pflynn is correct in suggesting using malloc.

However the base requirement is not reasonable. As far as I can see. You already have strings in **argv.

If you need to call them something useful like one, two and three ( you make up meaningful names) use pointers. Duplicating them serves no logical purpose except to use memory. The only time you would care about duplicating them is when both of these are true:

1. you need to keep them for later use, unchanged

2. you plan to change them (The C standard says you can modify them, you cannot tack more characters onto the end of each one, though). If you are concatenating **argv strings onto one of the **argv strings, then create duplicates.

otherwise use pointers to those strings. simple example:

Code:

#include <stdlib.h>
#include <errno.h>
int main(int argc, char **argv)
{
    char *one=argv[1];
    char *two=argv[2];
    char *three=argv[3];
    if(argc!=4)  // we want 3 parameters, as an example
    {
         errno=EINVAL;
         perror("3 parameters required, no more, no less");
         exit(1);
     }
     // do things with one, two && three 
     return 0;
}

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LEARN ABOUT CENTOS

tcl_concat

Tcl_Concat(3)						      Tcl Library Procedures						     Tcl_Concat(3)

__________________________________________________________________________________________________________________________________________________

NAME

       Tcl_Concat - concatenate a collection of strings

SYNOPSIS

       #include <tcl.h>

       const char *
       Tcl_Concat(argc, argv)

ARGUMENTS

       int argc (in)			      Number of strings.

       const char *const argv[] (in)	      Array of strings to concatenate.	Must have argc entries.
_________________________________________________________________

DESCRIPTION

       Tcl_Concat is a utility procedure used by several of the Tcl commands.  Given a collection of strings, it concatenates them together into a
       single string, with the original strings separated by spaces.  This procedure behaves differently than Tcl_Merge, in that the arguments are
       simply  concatenated:  no  effort  is made to ensure proper list structure.  However, in most common usage the arguments will all be proper
       lists themselves;  if this is true, then the result will also have proper list structure.

       Tcl_Concat eliminates leading and trailing white space as it copies strings from argv to the result.  If an element  of	argv  consists	of
       nothing but white space, then that string is ignored entirely.  This white-space removal was added to make the output of the concat command
       cleaner-looking.

       The result string is dynamically allocated using Tcl_Alloc;  the caller must eventually release the space by calling Tcl_Free.

SEE ALSO

       Tcl_ConcatObj

KEYWORDS

       concatenate, strings

Tcl									7.5							     Tcl_Concat(3)

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