软件设计⑦|单例模式

一、单例模式

https://baike.baidu.com/item/%E5%8D%95%E4%BE%8B%E6%A8%A1%E5%BC%8F/5946627?fr=aladdin

二、代码

（1）效果图

（2）代码

student.h

#pragma once
#ifndef _SINGLETON_H_
#define _SINGLETON_H_

class Student
{
public:
    static Student* GetInstance();
protected:
    Student();
private:
    static Student* _instance;
};

#endif

student.cpp

#include "student.h"
#include <iostream>
using namespace std;

Student* Student::_instance = 0;

Student::Student()
{
    cout << "create ..." << endl;
}

Student* Student::GetInstance()
{
    if (0 == _instance)
    {
        _instance = new Student();
    }
    else
    {
        cout << "already exist" << endl;
    }

    return _instance;
}

int main()
{
    Student* t = Student::GetInstance();
    t->GetInstance();

    return 0;
}

参考链接：https://www.jb51.net/article/55969.htm