Thread: for loop again. I don't understand the construction.

Hmm.... Dave, you there? I'm not seeing this. I suppose if all else fails, I'll clean up the wording and post the same question comp.unix.programmer. I'm trying to avoid that route because it takes me like 10 days to make heads or tails out of some of the responses I get.

cdalten.....

First, keep in mind that I haven't had a second cup of coffee yet, and I usually need that to be anything remotely resembling sharp. Second, I'm performing a massive brain context switch here at the moment, but this beats working on the problem I'm stuck on.....

Code:

char **h_aliases

Is a pointer to an array of strings. It can also be expressed as:

Code:

char *h_aliases[ ]

That means that you can find the members of that array as either:

Code:

hp->h_aliases[0]   /* first array member */
hp->h_aliases[1]  /* second array member */

/* or */
/* create a pointer to the first member.... */

char const*const* alias = hp->h_aliases;  

/* and traverse the array by incrementing the pointer */

++alias;

When trying to wrap your brain around this, you can ignore (For now) the const keywords -- he's just saying that he's not going to modify the pointer or the contents....

Hope I shed a little light on this.... I'm going for coffee now

The coffee's ready?

cdalten, it may be easier to think about this using the parameterized declaration of main; argv is very similar in usage to h_aliases. At least I'm hoping that it somehow can help clear the fog this way.

Code:

#include <stdio.h>

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

   for ( i = 0; argv[i] != NULL; ++i )
   {
      puts(argv[i]);
   }

   for ( arg = argv; *arg != NULL; ++arg )
   {
      puts(*arg);
   }
   return 0;
}

/* my output
H:>test one two three
H:\test.exe
one
two
three
H:\test.exe
one
two
three
*/

Originally Posted by Dave_Sinkula

The coffee's ready?

We're lucky here. We have one of those one-cup coffee makers with the little K-cups. It can be ready any time I drag my butt down to the break room

Thanks for clarifying the explanation. I never thought about telling cdalten about argv.