C Question

How do i pass a character pointer to an array into another function so that function can manipulate it?
I have a c program with everything in the main method and i want to simplify it, but i cant successfully pass a char *[] to another function.

helper(char *p);

int main(){
 char *p[100];
 helper(p);
 
 return 0;
}


void helper(char *p){
 //do stuff with p[0],p[1], etc
}

This isn't the board you are looking for.

Go here instead: http://7chan.org/halp

>>2
Yeah, we have to many incompetent fucks like this guy who's never written a line of c code in his life

>>3
So let's teach.  There'd be fewer around if we actually did a case by case assessment.

but i cant successfully pass a char *[] to another function
That's because your function expects an array of characters, not an array of pointers to chars.

>>1
So here you have declared an array of 100 character pointers, yes? They don't point to anything; indeterminate garbage. You then want to pass this array of pointers to a function, presumably so you can manipulate the character's the pointer's point to?
char *p[100];

An array is already a pointer. So p is a pointer to a pointer that points to a char. Ok? So p is pointer to the first character pointer.

void func(char *p)
{
   *(p + 0) = 'x'; #Store x at the location pointed to by p.
   *(p + 1) = 'y'; #Store y at the location pointed to by
                   #1 element from the first (the second pointer
                   #).
   #. . .
}

It might be helpful to do something like:
const int my_len = 100;
char *p[my_len];
and then pass my_len to your function as well to easily know how many pointers there are.

I have only proved this correct not tested it.

i think the OP might like this:
http://www.antlr.org/wiki/display/CS652/How+To+Read+C+Declarations

>>5,6
YOU HELPED HIM!

>>8

fuck you faggot

>>9
You don't understand, do you? If you help them, they'll stay. They'll keep posting threads about the most basic programming questions and then they'll bring in their friends to do the same. And then this place will turn into /halp/. If you have such an urge to HELP THEM, just direct them to http://7chan.org/halp and help them there.

>>10
The content in this place hardly counts as decent quality as it is, so it shouldn't matter.

>>11
There's nothing so bad that it can't get worse.

>>12
True. But if look at quality logarithmic scale:
bad quality ====|===========|====================================== good quality
                |           |
                |         "help me" thread
        prog average thread

you'll see that help me threads actually improve quality of content on this board.


#include <stdlib.h>
#include <stdio.h>

void my_func(char **p, int len)
{
   int i;
   for(i = 0; i < len; i++)
   {
      *(p + i) = 'x';
   }
   return;
}

int main(int argc, char **argv)
{
   const int my_len = 100;
   char *p[my_len];
   int i;

   //Initialize to NULL.
//for(i = 0; i < my_len; i++) p[i] = NULL;

   //Allocate space for characters.
   for(i = 0; i < my_len; i++)
   {
      p[i] = malloc(sizeof(char));
      if(p[i] == NULL)
      {
    goto cleanup;
      }
   }

   //Set characters.
   my_func(p, my_len);

  //Print characters proving they were set.
  for(i = 0; i < my_len; i++)  printf("%c\n", *(p + i));

  cleanup:
  //left as an excersise to the reader
   return 0;
}
>>1

>>13
There are ``help me'' threads ``and help'' me threads. Having to explain to someone on /prog/ the difference between a string and an array of character pointers is kinda depressing.

s/``and help'' me/and ``help me''/

>>13
THIS IS WHAT YOU ACTUALLY BELIEVE