内：

#include 
     
      class Singleton{public:    static Singleton *GetInstance()    {        return m_pSingletom;    }        int function() {        return 0;    }private:    static Singleton *m_pSingletom;    // 构造私有函数    Singleton()    {        if (m_pSingletom == NULL) {            m_pSingletom = new Singleton();        }    }};Singleton *Singleton::m_pSingletom = 0;int main(int argc, const char * argv[]){    Singleton *single = Singleton::GetInstance();    int n = single->function();        printf("%d\n",n);    std::cout << "Hello, World!\n";    return 0;}
     

外

.h#ifndef __SingletonDemo__Test__#define __SingletonDemo__Test__#include 
     
      class Singleton{public:    static Singleton *GetInstance();    int function();private:    static Singleton *m_pSingleton;};#endif /* defined(__SingletonDemo__Test__) */
     

.cpp#include "Test.h"Singleton *Singleton::m_pSingleton = NULL;Singleton *Singleton::GetInstance(){    if (Singleton::m_pSingleton == NULL) {        Singleton::m_pSingleton = new Singleton();    }        return m_pSingleton;}int Singleton::function(){    return 9;}