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

int main(void)
{
	int *v1;

	v1 = malloc(5 * sizeof(*v1));
	if (NULL == v1) {
		perror("malloc");
		exit (EXIT_FAILURE);
	}

	/* overflow */
	v1[6] = 100;

	free(v1);

	/* write after free */
	v1[6] = 100;

	/* reallocate v1 */
	v1 = malloc(10 * sizeof(int));
	if (NULL == v1) {
		perror("malloc");
		exit (EXIT_FAILURE);
	}

	return 0;
}