malloc，free实验

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

int main()
{
	char a = 0;
	//int * p = (int * ) malloc (4 * sizeof(int));
	int * p = (int * ) malloc (4);
	char * cp = (char * ) malloc (4 * sizeof(char));

	a = 1;
	a = (char)(~0);
	a = 0;
	a |= (~((~0)<<5) <<3);
	
	//step-by-step program
	a = 0;
	a = (char)(~0);
	a = a << 5;
	a = ~a;
	a = a << 3;

	if(NULL == p)
	{
		printf("malloc failed\n");
		return -1;
	}

	if(NULL == cp)
	{
		printf("malloc failed\n");
		return -1;
	}

	*(p+0) = 1;
	*(p+1) = 3;
	*(p+2) = 5;
	*(p+3) = 4;
	*(cp+0) = 1;
	*(cp+1) = 3;
	*(cp+2) = 5;
	*(cp+3) = 4;
	//*(p+4) = 6; //编译通过，但无法运行。
	printf("%d\n", *(p+3));

	free (p);

	free (cp);
	
	return 0;
}