簡(jiǎn)介

????????所謂原型模式就是用原型實(shí)例指定創(chuàng)建對(duì)象的種類碱屁，并且通過復(fù)制這些原型創(chuàng)建新的對(duì)象忽媒。舉一個(gè)簡(jiǎn)單的例子腋粥，一個(gè)人想要批量分發(fā)自己的名片，然而名片千篇一律隘冲，只是偶爾修改一些地方，但需求量大奥邮，所以需要不斷實(shí)例化名片類罗珍，十分麻煩，所以這就有了原型模式蘸朋。原型模式旨在以某一類為原型扣唱，利用Clone成員函數(shù)不斷拷貝出新對(duì)象。
????????在C++中噪沙，有淺拷貝和深拷貝兩種拷貝模式，默認(rèn)賦值采用淺拷貝的方法辐马，但淺拷貝會(huì)共享分配的堆椌忠澹空間，析構(gòu)時(shí)會(huì)兩次釋放空間導(dǎo)致程序崩潰贞奋，所以原型模式一般直接使用深拷貝穷绵，由拷貝構(gòu)造函數(shù)實(shí)現(xiàn)。
????????下面我們就以印名片為例子為大家講解一下原型模式的用法。

圖示

原型模式圖示

代碼實(shí)現(xiàn)

////////////////////////////
//
// FileName : ProtoTypeDefine.h
// Editor : PeterZheng
// Date : 2018/8/16 18:00
//
////////////////////////////

#pragma once

#ifndef PROTOTYPE_H_
#define PROTOTYPE_H_

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <string>
#include <windows.h>

#endif

#define MAX_LENGTH 255

//克隆抽象類
class ProtoType
{
public:
    virtual ProtoType* Clone() = 0;
};

//克隆具體實(shí)現(xiàn)類（名片類）
class ConcreteProtoType
{
public:
    int age;
    char* name;
    char* school;
    ConcreteProtoType(int a, const char* name, const char* school)
    {
        this->age = a;
        this->name = new char[MAX_LENGTH];
        this->school = new char[MAX_LENGTH];
        ZeroMemory(this->name, MAX_LENGTH);
        ZeroMemory(this->school, MAX_LENGTH);
        strcpy_s(this->name, MAX_LENGTH, name);
        strcpy_s(this->school, MAX_LENGTH, school);
    }
    ConcreteProtoType(const ConcreteProtoType& pt)
    {
        this->age = pt.age;
        this->name = new char[MAX_LENGTH];
        this->school = new char[MAX_LENGTH];
        ZeroMemory(this->name, MAX_LENGTH);
        ZeroMemory(this->school, MAX_LENGTH);
        strcpy_s(this->name, MAX_LENGTH, pt.name);
        strcpy_s(this->school, MAX_LENGTH, pt.school);
    }
    ~ConcreteProtoType() {}
    ConcreteProtoType* Clone()
    {
        return new ConcreteProtoType(*this);
    }
    void Show()
    {
        std::cout << "Name: " << this->name << std::endl << "Age: " << this->age << std::endl << "School: " << this->school << std::endl;
    }
};

////////////////////////////
//
// FileName : ProtoTypeDemo.cpp
// Editor : PeterZheng
// Date : 2018/8/16 19:22
//
////////////////////////////

#include "ProtoTypeDefine.h"

using namespace std;

int main(void)
{
    ConcreteProtoType *mp1 = new ConcreteProtoType(28, "XiaoMin", "CMU");
    ConcreteProtoType *mp2 = mp1->Clone();
    //名片的學(xué)校需要改為MIT
    ConcreteProtoType *mp3 = new ConcreteProtoType(28, "XiaoMin", "MIT");
    ConcreteProtoType *mp4 = mp3->Clone();
    mp1->Show();
    cout << endl;
    mp2->Show();
    cout << endl;
    mp3->Show();
    cout << endl;
    system("pause");
    return 0;
}