Thread: Dynamic allocation (I thought it would crash)

I've been trying to learn a bit about dynamic allocation in my noobish way, and I decided to see what would happen if I deliberately tried to cram too much data into a memory block that is too small to contain it all. Ironically the program seems to function correctly, printing out the full array, even though I've tried to make it overload. I can't figure out why.

Code:

/* Dynamic memory allocation */

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

int main()
{
   char size[5];   // Array deliberately set too small
   int *memory_block;
   int i;
   char word[] = "abcdefghijklmnopqrs";
   char c;

   /* Allocate memory defined by char array 'size' */
   memory_block = malloc(sizeof(size));
   
   /* Check for allocation failure */
   if(memory_block == NULL)
   {
      printf("Allocation Failed.\n");
      exit(EXIT_FAILURE);
   }else
      printf("Memory Allocated.\n");

   /* Copy data stored in 'word' into 'memory_block' */
   for(i = 0; word[i]; i++)
   {
   memory_block[i] = word[i];
   printf("%c\n", memory_block[i]);   
   }

   /* Return memory to heap */
   free(memory_block);

   /* Exit */
   printf("Press 'q' to exit:");
   if((c = _getch()) == 'q')
      return 0;
}

Output:

Memory Allocated
a
b
c
d
e
f
............
s
Press 'q' to exit: