#include <stdio.h>   /* C example */
#include <stdlib.h>

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

	printf("How many char's do you want to allocate? ");
	scanf("%u", &n);   /* not portable */

	p = malloc(n * sizeof (char));
	if (p == NULL) {
		fprintf(stderr, "%s: can't allocate %u char's\n", argv[0], n);
		return EXIT_FAILURE;
	}

	p[0] = 'A';        /* or *p = 'A'; */
	p[1] = 'B';
	p[2] = 'C';
	/* etc. */
	p[n - 1] = '\0';   /* Warning: the subscripts only go up to n - 1. */

	printf("The hidden numbers are %u and %u.\n", /* unofficial; not portable */
		((size_t *)p)[-2], ((size_t *)p)[-1]);

	free(p);
	return EXIT_SUCCESS;
}