3-16.txt

vc++源代码 适合于开发各种程序 也可以用于学习

/* 范例：3-16  void指针 */
#include <stdio.h>
void main(void)
{
  int a = 6838;
  int *p;
  printf("&p=%u :%d bytes\n", &p, sizeof(&p));
  p = &a;
  printf("*p = %d   p = %u\n", *p, p);
  printf(" a = %d  &a = %u", a, &a);
  printf("\n-------------------------------------");
  /*-------------------------------------------------------------------------*/
  int i;
  float r;
  void *poin = &i;	/* 取i的地址存放到指针变量poin中 */
  *(int *)poin = 2;	/* 设定void类型指针变量poin指向的变量(i)为2 */
  poin = &r;	/* 取浮点变量r的地址存放到poin，因此目前poin指向变量r */
  *(float *)poin = 2.3;	/* 按照地址操作值, 将r值设定为2.3 */
  printf("\n*poin = %d   poin = %u\n", *(int *)poin, poin);
  printf("\n*poin = %f   poin = %u\n", *(float *)poin, poin);
  printf("i = %d  &i = %u", i, &i);

  getchar();
}

程序执行结果﹕
&p=6618620 :4 bytes
*p = 6838   p = 6618624
 a = 6838  &a = 6618624
-------------------------------------
*poin = 1075000115   poin = 6618612
*poin = 2.300000   poin = 6618612
i = 2  &i = 6618616