C++单例写法记录

C++单例写法记录

• 源码地址

一、饿汉式

1.1 静态指针、静态垃圾回收类

1. instance.h

   #ifndef INSTANCE_H
   #define INSTANCE_H
   #include 
   #include 
   
   class Instance01{
   private:
       class Garbo{
       public:
           ~Garbo();
       };
   
   private:
       Instance01(){std::cout << "Instance01 的构造函数" << std::endl;}
       ~Instance01(){std::cout << "Instance01 的析构函数" << std::endl;}
   
       Instance01(const Instance01& instance) = delete;
       Instance01& operator=(const Instance01& Instance) = delete;
   
   public:
       static Instance01* GetInstance();
   
       /*
           其他成员函数
       */
       std::string GetName(); 
   
   private:
       static Instance01* instancePtr;
       static Garbo garbo;
   
       /*
           其他成员变量
       */
       std::string name = "I am Instance01"; 
   };
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2. instace.cpp

   #include 
   #include "instance.h"
   // 类的静态成员变量声明
   Instance01* Instance01::instancePtr = new Instance01();
   Instance01::Garbo Instance01::garbo;
   
   // 内存回收
   Instance01::Garbo::~Garbo(){
       if(instancePtr != nullptr){
           delete instancePtr;
           instancePtr = nullptr;
       }
   }
   
   // 获取实例地址
   Instance01* Instance01::GetInstance(){
       return instancePtr;
   }
   
   // 其他业务逻辑
   std::string Instance01::GetName(){
       return name;
   }
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1.2 静态成员

1. instance.h

   #ifndef INSTANCE_H
   #define INSTANCE_H
   #include 
   #include 
   
   class Instance02{
   private:
       Instance02(){std::cout << "Instance02 的构造函数" << std::endl;}
       ~Instance02(){std::cout << "Instance02 的析构函数" << std::endl;}
   
       Instance02(const Instance02& instance) = delete;
       Instance02& operator=(const Instance02& Instance) = delete;
   
   public:
       static Instance02* GetInstance();
   
       /*
           其他成员函数
       */
       std::string GetName(); 
   
   private:
       // 静态成员，程序结束自动释放内存
       static Instance02 instance;
   
       /*
           其他成员变量
       */
       std::string name = "I am Instance02"; 
   };
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2. instace.cpp

   #include 
   #include "instance.h"
   
   // 类的静态成员变量声明
   Instance02 Instance02::instance;
   
   // 获取实例地址
   Instance02* Instance02::GetInstance(){
       return &instance;
   }
   
   // 其他业务逻辑
   std::string Instance02::GetName(){
       return name;
   }
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1.3 测试

1. main.cpp

   #include 
   #include "instance.h"
   
   int main(void){
       std::cout << Instance01::GetInstance()->GetName() << std::endl;
       std::cout << Instance02::GetInstance()->GetName() << std::endl;
       return 0;
   }
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2. 结果