单例模式

在设计模式里面最简单的要属单例模式了，我打算把GOF书上的设计模式都实践一遍，先给出单例模式的代码：

#pragma onceclass Singleton{private:static Singleton* instance;Singleton(){}public:static Singleton* Instance(){if(instance==NULL)instance=new Singleton();return instance;}~Singleton(){if(instance!=NULL)delete instance;}};Singleton* Singleton::instance=NULL;

下面这是测试代码

#include <iostream>#include <cstdlib>#include "Singleton.h"using namespace std;int main(int argc , char **argv){Singleton *p=Singleton::Instance();Singleton *q=Singleton::Instance();if(p==q)printf("They are equal\n");system("pause");return EXIT_SUCCESS;}