#include <stdio.h>
#include <stdlib.h>  // for malloc
#include <error.h>

#define ARRAY_SIZE 10

int main(int argc, char **argv) {
  int *p;

  // dirty some memory
  p = (int*)malloc(ARRAY_SIZE * sizeof(int));  // takes size in bytes
  if ( p == NULL ) error(1, 0, "Out of memory!");
  for (int i=0; i<ARRAY_SIZE; i++) {
    p[i] = i+1;
  }
  free(p);

  // malloc doesn't initialize the memory it allocates
  p = (int*)malloc(ARRAY_SIZE * sizeof(int));  // takes size in bytes
  if ( p == NULL ) error(1, 0, "Out of memory!");
  printf("\npost-malloc:\n");
  for (int i=0; i<ARRAY_SIZE; i++) {
    printf("%d ", p[i]);
  }
  printf("\n");
  free(p);

  // calloc zeroes the memory it allocates
  p = (int*)calloc(sizeof(int), ARRAY_SIZE);  // takes size of each elemenet and #elements
  if ( p == NULL ) error(1, 0, "Out of memory!");
  printf("\npost-calloc:\n");
  for (int i=0; i<ARRAY_SIZE; i++) {
    printf("%d ", p[i]);
  }
  printf("\n");
  free(p);

  return 0;
}