相關概念參考：【C++】C++ 單例模式總結（5種單例實現方法）_單例模式c++實現-CSDN博客

#include<iostream>class LazySingle{
public:static LazySingle& getInstance(){static LazySingle instance;return instance;}void hello(){std::cout<<"Congratulations"<<std::endl;}private:LazySingle(){};
};
class LazySinglePtr{public:static LazySinglePtr* getInstance(){static LazySinglePtr instance;return &instance;}void hello(){std::cout<<"Congratulations"<<std::endl;}private:LazySinglePtr(){};
};class HungrySingle{
public:static HungrySingle& getInstance(){return instance_;}private:static HungrySingle instance_;HungrySingle(){};
};HungrySingle  HungrySingle::instance_;int main(){std::cout<<"懶漢引用模式:"<<std::endl;auto& lazy1=LazySingle::getInstance();LazySingle& lazy2=LazySingle::getInstance();std::cout<<" lzay1="<<&lazy1<<" lzay2="<<&lazy2<<" instance="<<&LazySingle::getInstance()<<std::endl;lazy1.hello();std::cout<<"懶漢指針模式:"<<std::endl;auto lazyptr1=LazySinglePtr::getInstance();LazySinglePtr* lazyptr2=LazySinglePtr::getInstance();std::cout<<" lzay1="<<lazyptr1<<" lzay2="<<lazyptr2<<" instance="<<LazySinglePtr::getInstance()<<std::endl;lazyptr1->hello();std::cout<<"餓漢模式:"<<std::endl;HungrySingle& hungry1=HungrySingle::getInstance();HungrySingle& hungry2=HungrySingle::getInstance();std::cout<<" hungry1="<<&hungry1<<" hungry2="<<&hungry2<<" instance="<<&HungrySingle::getInstance()<<std::endl;return 0;}

輸出：

懶漢引用模式:lzay1=0x7ff61a279e90 lzay2=0x7ff61a279e90 instance=0x7ff61a279e90
Congratulations
懶漢指針模式:lzay1=0x7ff61a279ee0 lzay2=0x7ff61a279ee0 instance=0x7ff61a279ee0
Congratulations
餓漢模式:hungry1=0x7ff61a2aa030 hungry2=0x7ff61a2aa030 instance=0x7ff61a2aa030

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