/*
** $Id: memory.c 774 2008-02-16 01:24:16Z phf $
**
** Very simple first example of using malloc() and free()
** for dynamic memory allocation. Note: Don't ever free()
** anything you did not malloc() previously, it's plain
** wrong, somewhat mean, and just a hassle in the end.
**
** Note that I should do more complete error checking in
** the code below, but I don't have time since I need to
** post this ASAP. I just use assert() where you should
** do *real* error checking. Sorry.
*/

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

int main(int argc, char *argv[])
{
  // make sure we have an argument
  assert(argc > 1);

  // We'll let the user specify how large an array we
  // should build.
  int size = (int) strtol(argv[1], NULL, 10);

  // make sure the size is positive
  assert(size > 0);
  
  // Now we'll actually get the memory for an array
  // of that size.
  int *array = malloc(size * sizeof(int));

  // make sure we got the memory
  assert(array != NULL);

  // Compute a table of squares, just to do something
  // that initializes the array; malloc() does *not*
  // promise that everything will be set to 0, might
  // want to use calloc() for that...
  for (int i = 0; i<size; i++) {
    array[i] = i*i;
  }

  // And print the array again, nothing interesting
  // hiding here... :-)
  for (int i = 0; i<size; i++) {
    printf("array[%d] == %d\n", i, array[i]);
  }

  // Now that we're done with using it, let's free
  // the memory again. Not *strictly* necessary as
  // we're about to exit anyway, but it shows good
  // taste and proves that you know what to do...
  free(array);

  // And we're done. :-)
  return EXIT_SUCCESS;
}