Thread: Questions regarding char *argv[ ]...

I'm working on a program that accepts command line arguments and I was wondering if it would be OK to hard code the search pattern for argv[ ] because you already know what it's going to be looking for.
ex:

Code:

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

        for(i = 0; *argv[1][i] != " "; i++)
        {
               if(*argv[1][i] == "-")
                        i++;
               if(*argv[1][i] == "r")
                       //more statements here etc etc
        }
}

Is that an acceptable way to search for command line options?
Is there a better way that anyone has found?
Thanks for any advise.

You are comparing strings with characters. argv[x][y] is a single character. "x" is a string consisting of the letter x and the terminating zero-character. You can not compare strings this way in C (nor do you need to in this case).

--
Mats

Originally Posted by root4

what you're trying to do is probably something like:

Code:

  if(!strncmp(argv[1],"-r",3)) { ... }

Note that command line processing functions already exist (getopt, etc.).
This is generally a bad practice to impose the CL argument order (from the user point of view) but if for some reason you think this is acceptable (for instance for an automatic call by a tool and not by a human), then why not.

No, I expect a human to use my code. Thanks for the advice, I'll read up on that and similar functions.
Thank you.

Also note that since argv is char**, you cannot do *argv[n][n]. argv[n] gives a char*, and argv[n][n] gives a char.

Originally Posted by Elysia

Also note that since argv is char**, you cannot do *argv[n][n]. argv[n] gives a char*, and argv[n][n] gives a char.

OK, so I was way off.
I thought (wrongfully so, apparently) that

Code:

*++argv[i][j]

would point to the the j-th character of the i-th character of argv.
I presume I am incorrect in this assumption?
Thanks again.

Point to?
argv[i][j] is the j-th character of i-th string. Basically.
Don't forget to check argc to see the number of arguments actually passed.

Originally Posted by Elysia

Point to?
argv[i][j] is the j-th character of i-th string. Basically.
Don't forget to check argc to see the number of arguments actually passed.

noted. Thanks for everyone's help.