c++单例模式[1]--懒汉式基础版

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单例模式
基本版–单线程

#pragma once
#include <iostream>
#include <thread>
/**
 *单例模式标准实现 5步走（懒汉式）
 1静态私有实例指针
 2拷贝赋值私有化
 3构造析构私有化
 4全局访问与释放
 5静态内部实例指针全局实例
 *Date :[10/9/2018 ]
 *Author :[RS]
 */
using namespace std;
class Singleton1 {
private:
	Singleton1() {
		cout << "构造 begin" << endl;
		this_thread::sleep_for(chrono::seconds(1));
		cout << "构造 over" << endl;
	}
	virtual ~Singleton1() {
		cout << "构造" << endl;
	}
private:
	Singleton1(const Singleton1&) = delete;
	Singleton1& operator=(const Singleton1) = delete;
public:
	static Singleton1* GetInstance() {
		if (nullptr == mInstance) {
			mInstance = new Singleton1;
		}
		return mInstance;
	}
	static void RelaceInstance() {
		if (nullptr != mInstance) {
			delete mInstance;
			mInstance = nullptr;
		}
	}
public:
	void print() {
		cout << "打印实例内存指针：" << mInstance << endl;;
	}

private:
	static Singleton1 * mInstance;
};
Singleton1* Singleton1::mInstance = NULL;

测试方法

#include "Singleton1.hpp"

void main() {
	auto ss = Singleton1::GetInstance();
	ss->print();
	auto ss2 = Singleton1::GetInstance();
	ss2->print();
	system("pause");
}

测试结果