Thread: Array of pointers

I cannot get it work.
The function returnPointer() returns pointer for every string I've inserted until it returns null value. I want to store all of these returned pointers in a dynamic array named arrayOfPointers in the way that I can print out all these stored strings later. The main function doesn't work correctly. It just crashes (altough it seems to store some pointers in arrayOfPointers). I think that there is something wrong with variable q after passing through the while loop in the main function for the first time.

Code:

#include <stdlib.h>
#include <stdio.h>
#include <malloc.h>
#include <string.h>
char * returnPointer();

int main ( void )
{
  char *q = NULL;
  char **arrayOfPointers = NULL;
  int size2 = 0;
  int capacity2 = 0;
  do 
  {
    if ( size2 == capacity2 ) 
    {
      capacity2 += 1;
      arrayOfPointers = realloc ( q, capacity2 + 1 );
    }
    q = returnPointer();
    arrayOfPointers[size2++] = q;
    //printf("%d\n",arrayOfPointers[size2]);
  } while (q != NULL);
  free(arrayOfPointers);
  return 0;
}

char * returnPointer()
{
  char *s = NULL;
  int size = 0;
  int capacity = 0;
  int ch;
  printf("Insert something\n");
  while ( ( ch = getchar() ) != '\n' && ch != EOF ) 
  {
    if ( size == capacity ) 
    {
      char *save;
      capacity += 5;
      save = realloc ( s, capacity + 1 );
      if ( save == NULL )
        break;
      s = save;
    }
    s[size++] = ch;
  }

  if ( size > 0 ) 
  {
    s[size] = '\0';
  }
  return s;
}

Originally Posted by Salem

> arrayOfPointers = realloc ( q, capacity2 + 1 );
1. Follow the same idea in the called function.
You want arrayOfPointers = realloc ( arrayOfPointers, capacity2 + 1 ); with the temp variable.

2. You need to multiply the amount by the size.

1. Do you mean variable 'save' by variable 'temp' as an example from called function?
2. I don't understand what you mean by that sentence. I cannot distinguish amount and size at the moment.

Ok, it seems to work now. Just want to know why there is no need to multiply amount by size in returnPointer() function as I did in the main function?

Code:

int main ( void )
{
  char *q = NULL;
  char **arrayOfPointers = NULL;
  int size2 = 0;
  int capacity2 = 0;
  int i=0;
  do 
  {
    if ( size2 == capacity2 ) 
    {
      char **save2;
      capacity2 += 1;
      save2 = realloc (arrayOfPointers, (capacity2 + 1)*sizeof(save2) );
      if ( save2 == NULL )
        break;
      arrayOfPointers = save2;
    }
    q = returnPointer();
    arrayOfPointers[size2++] = q;
    printf("%s\n",*(arrayOfPointers+i));
    i++;
  } while (q != NULL);
  free(arrayOfPointers);
  return 0;
}