char **tab;

  // allocation
  tab = malloc(5 * sizeof(char*));
  for(int j=0 ; j<5 ; j++)
    {
      tab[j] = malloc(4 * sizeof(char));
    }

  // FILL TAB FIRST WAY
  /*
  for(int j=0 ; j<5 ; j++)
    {
      for(int i=0 ; i<4 ; i++)
        {
          tab[j][i] = '@';
        }
    }
  */

  // FILL TAB SECOND WAY
  for(int j=0 ; j<5 ; j++)
    {
      tab[j] = "@@@@";
    }

  //free
  for(int j=0 ; j<5 ; j++)
    {
      free(tab[j]);
    }

  free(tab);

HEAP SUMMARY:
==447==     in use at exit: 20 bytes in 5 blocks
==447==   total heap usage: 6 allocs, 6 frees, 60 bytes allocated
==447==
==447== Searching for pointers to 5 not-freed blocks
==447== Checked 64,648 bytes
==447==
==447== LEAK SUMMARY:
==447==    definitely lost: 20 bytes in 5 blocks
==447==    indirectly lost: 0 bytes in 0 blocks
==447==      possibly lost: 0 bytes in 0 blocks
==447==    still reachable: 0 bytes in 0 blocks
==447==         suppressed: 0 bytes in 0 blocks
==447== Rerun with --leak-check=full to see details of leaked memory
==447==
==447== ERROR SUMMARY: 5 errors from 1 contexts (suppressed: 0 from 0)
==447==
==447== 5 errors in context 1 of 1:
==447== Invalid free() / delete / delete[] / realloc()
==447==    at 0x4C2EDEB: free (in /usr/lib/valgrind/vgpreload_memcheck-
amd64-linux.so)
==447==    by 0x400607: main (test_malloc.c:35)