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23种设计模式--单例模式（懒汉） 
 1 #include "stdafx.h"
 2 
 3 //单例模式之懒汉模式
 4 class Singleton
 5 {
 6 public:
 7     static Singleton& GetInstance()
 8     {
 9         if(m_spInstance==NULL)
10         {
11             m_spInstance = new Singleton;
12         }
13         m_snCount++;
14         return *m_spInstance;
15     }
16     void ReleaseInstance()
17     {
18         m_snCount--;
19         if(m_snCount==0)
20         {
21             delete m_spInstance;
22         }
23     }
24     ~Singleton()
25     {
26         m_spInstance=NULL;
27     }
28 private:
29     //构造,拷贝构造
30     Singleton() {}
31     Singleton(Singleton& singleton)    {}
32     //单例指针
33     static Singleton *m_spInstance;
34     //引用计数
35     static unsigned int m_snCount;
36 };
37 Singleton* Singleton::m_spInstance=NULL;
38 unsigned int Singleton::m_snCount=0;
39 
40 //测试用例
41 int main(int argc, char* argv[])
42 {
43     Singleton& s1 = Singleton::GetInstance();
44     Singleton& s2 = Singleton::GetInstance();
45     printf("%p\n%p\n",&s1,&s2);
46     s1.ReleaseInstance();
47     s2.ReleaseInstance();
48     return 0;
49 }
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注：该代码在VC6.0下测试通过

posted on 2013-07-27 10:02  时光飞逝~  阅读(220)  评论(0)    收藏  举报