易采站长站为您分析C++编程中对设计模式中的原型模式的使用实例,包括原型模式中对C++的深拷贝和浅拷贝的处理,需要的朋友可以参考下
原型模式的实现完整代码示例（code）：原型模式的实现很简单，这里为了方便初学者的学习和参考，将给出完整的实现代码（所有代码采用 C++实现，并在 VC 6.0 下测试运行）。
代码片断 1：Prototype.h
//Prototype.h
#ifndef _PROTOTYPE_H_
#define _PROTOTYPE_H_
class Prototype{
public:
virtual ~Prototype();
virtual Prototype* Clone() const = 0;
protected:
Prototype();
private:
};
class ConcretePrototype:public Prototype{
public:
ConcretePrototype();
ConcretePrototype(const ConcretePrototype& cp);
~ConcretePrototype();
Prototype* Clone() const;
protected:
private:
};
#endif //~_PROTOTYPE_H_
代码片断 2：Prototype.cpp
//Prototype.cpp
#include "Prototype.h"
#include <iostream>
using namespace std;
Prototype::Prototype(){
}
Prototype::~Prototype(){
}
Prototype* Prototype::Clone() const{
return 0;
}
ConcretePrototype::ConcretePrototype(){
}
ConcretePrototype::~ConcretePrototype(){
}
ConcretePrototype::ConcretePrototype(const ConcretePrototype& cp){
cout<<"ConcretePrototype copy ..."<<endl;
}
Prototype* ConcretePrototype::Clone() const{
return new ConcretePrototype(*this);
}
代码片断 3：main.cpp
//main.cpp
#include "Prototype.h"
#include <iostream>
using namespace std;
int main(int argc,char* argv[]){
Prototype* p = new ConcretePrototype();
Prototype* p1 = p->Clone();
return 0;
}
代码说明：原型模式的结构和实现都很简单，其关键就是（C++中）拷贝构造函数的实现方式，这也是 C++实现技术层面上的事情。由于在示例代码中不涉及到深层拷贝（主要指有指针、复合对象的情况），因此我们通过编译器提供的默认的拷贝构造函数（按位拷贝）的方式进行实现。说明的是这一切只是为了实现简单起见，也因为本文档的重点不在拷贝构造函数的实现技术，而在原型模式本身的思想。
另一个实例
我们再来看一个具体项目的例子：
namespace Prototype_DesignPattern
{
using System;
// Objects which are to work as prototypes must be based on classes which
// are derived from the abstract prototype class
abstract class AbstractPrototype
{
abstract public AbstractPrototype CloneYourself();
}
// This is a sample object
class MyPrototype : AbstractPrototype
{
override public AbstractPrototype CloneYourself()
{
return ((AbstractPrototype)MemberwiseClone());
}
// lots of other functions go here!
}
// This is the client piece of code which instantiate objects
// based on a prototype.
class Demo
{
private AbstractPrototype internalPrototype;
public void SetPrototype(AbstractPrototype thePrototype)
{
internalPrototype = thePrototype;
}
public void SomeImportantOperation()
{
// During Some important operation, imagine we need
// to instantiate an object - but we do not know which. We use
// the predefined prototype object, and ask it to clone itself.
AbstractPrototype x;
x = internalPrototype.CloneYourself();
// now we have two instances of the class which as as a prototype
}
}
/// <summary>
/// Summary description for Client.
/// </summary>
public class Client
{
public static int Main(string[] args)
{
Demo demo = new Demo();
MyPrototype clientPrototype = new MyPrototype();
demo.SetPrototype(clientPrototype);
demo.SomeImportantOperation();
return 0;
}
}
}
