设计模式单例模式

Posted 2022-12-15 zhao111222333444

#include<iostream>
#include<mutex>
using namespace std;
class single
public:
	static single* get()
		return &s;
	

private:
	single();
	single(single &a) = delete;
	single& operator=(single &a) = delete;
	static single s;
;
single single::s;



class single2
public:
	static single2* get()
		if (_ptr == nullptr)
			_mutex.lock();
			if (_ptr == nullptr)
				_ptr = new single2;
			
			_mutex.unlock();
		
		return _ptr;
	
private:
	single2();
	single2(single2 &a) = delete;
	single2& operator=(single2 &a) = delete;
	static single2* _ptr;
	static mutex _mutex;
;
single2* single2::_ptr = nullptr;
mutex single2::_mutex;