零长度数组 

 1 /*
 2  * =====================================================================================
 3  *
 4  *       Filename:  zeroLengthArray.cpp
 5  *
 6  *    Description:  
 7  *
 8  *        Version:  1.0
 9  *        Created:  07/22/2011 01:56:35 AM
10  *       Revision:  none
11  *       Compiler:  gcc
12  *
13  *         Author:  Darius-Kylin (dyc), dongyuchi@gmail.com
14  *        Company:  UESTC
15  *
16  * =====================================================================================
17  */
18 #include<iostream>
19 #include<cstdlib>
20 using namespace std;
21 
22 struct device
23 {
24     int num;
25     int count;
26     int reserve[0];//reserve是一个数组名；该数组没有元素；该数组的其实地址紧随结构题device之后；这种声明方法可以巧妙的实现C/C++语言里的数组扩展
27 };
28 int main()
29 {
30     struct device *p_dev=(struct device*)malloc(sizeof(struct device)+sizeof(int)*25);
31     //sizeof(int)*25是数组reserve的具体空间(25个元素)
32     p_dev->reserve[0]=99;
33     p_dev->reserve[24]=0;
34     cout<<"p_dev->reserve[0]="<<p_dev->reserve[0]<<endl;
35     cout<<"p_dev->reserve[24]="<<p_dev->reserve[24]<<endl;
36     cout<<"sizeof(struct device)="<<sizeof(struct device)<<endl;
37     // 将结构体device之后的第一个内容(int值，其实就是reserve[0]的值)赋值给变量a
38     int a=*(&(p_dev->count)+1);
39     cout<<"a="<<a<<endl;
40     return 0;
41 }

　　

posted @ 2011-07-22 22:26  墨白麒麟  阅读(260)  评论(0)    收藏  举报