C++实现单例模式
编译环境VS2012。如题用C++实现单例模式，代码如下。
#ifndef SINGLETON_H#define SINGLETON_H#endif#ifndef _IOSTREAM_#include <iostream>#endif#ifndef _STRING_#include <string>#endif#ifndef _WINDOWS_#include <windows.h>#endifusing namespace std;class Singleton{private:std::string value;static Singleton* instance;Singleton(){};public:static Singleton* getInstance();std::string getValue();void setValue(char*);~Singleton();};Singleton* Singleton::instance = new Singleton;Singleton* Singleton::getInstance(){return instance;}string Singleton::getValue(){return this->value;}void Singleton::setValue(char* _value){this->value.assign(_value);}Singleton::~Singleton(){instance = NULL;delete instance;}int main(int __argc, char **__argv){Singleton* aaa = Singleton::getInstance();cout<<"Before set aaa value, aaa->value:\t"<<aaa->getValue()<<endl;aaa->setValue("bye 2012");cout<<"After set aaa value, aaa->value:\t"<<aaa->getValue()<<endl;Singleton* bbb = Singleton::getInstance();cout<<"Before set bbb value, bbb->value:\t"<<bbb->getValue()<<endl;bbb->setValue("hello 2013");cout<<"After set bbb value, bbb->value:\t"<<bbb->getValue()<<endl;cout<<"After set bbb value, aaa->value:\t"<<aaa->getValue()<<endl;Sleep(5000);return 0;}