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简单工厂模式:
自己的理解:一个类有多种子类,牵涉到要实例化某种子类,用工厂模式来生成对应的实例对象.
比如如下的计算器的设计:
Operation:操作类的基类
1 class Operation 2 { 3 public: 4 Operation(double lhs,double rhs):_numberA(lhs),_numberB(rhs){} 5 ~Operation(void); 6 virtual double GetResult() 7 { 8 double result = 0; 9 return 0; 10 } 11 double GetA() 12 { 13 return _numberA; 14 } 15 double GetB() 16 { 17 return _numberB; 18 } 19 private: 20 double _numberA; 21 double _numberB; 22 };
接下来对操作类有两个子类,分别实现加法和减法
1 class OperationAdd : 2 public Operation 3 { 4 public: 5 OperationAdd(double lhs,double rhs):Operation(lhs,rhs){} 6 double GetResult() 7 { 8 double result = 0; 9 result = GetA() +GetB(); 10 return result; 11 } 12 ~OperationAdd(void); 13 }; 14 15 class OperationSub:public Operation 16 { 17 public: 18 OperationSub(double lhs,double rhs):Operation(lhs,rhs){} 19 double GetResult() 20 { 21 double result=0; 22 result = GetA()-GetB(); 23 return result; 24 } 25 ~OperationSub(void); 26 };
然后实现工厂类,针对不同的输入产生不同的实例对象:
1 class OperationFactory 2 { 3 public: 4 static Operation* createOperate(double lhs,char operate,double rhs) 5 { 6 Operation *oper = NULL; 7 switch (operate) 8 { 9 case ‘+‘: 10 oper = new OperationAdd(lhs,rhs); 11 break; 12 case ‘-‘: 13 oper = new OperationSub(lhs,rhs); 14 break; 15 16 } 17 return oper; 18 } 19 OperationFactory(void); 20 ~OperationFactory(void); 21 };
代码调用:
int _tmain(int argc, _TCHAR* argv[]) { Operation *ptr; ptr = OperationFactory::createOperate(1.23,‘+‘,2.34); cout<<ptr->GetResult()<<endl; Operation *ptr2; ptr2 = OperationFactory::createOperate(1.23,‘-‘,2.34); cout<<ptr2->GetResult()<<endl; return 0; }
银行收银系统的工厂模式设计方法:(之后改成策略模式)
class CashSuper { public: virtual double acceptCash(double money)=0; CashSuper(void); ~CashSuper(void); };
#pragma once //不打折扣的情况 #include "cashsuper.h" class CashNormal : public CashSuper { public: virtual double acceptCash(double money) { return money; } CashNormal(void); ~CashNormal(void); };
#pragma once //打折扣的情况 #include "cashsuper.h" class CashRebate : public CashSuper { public: CashRebate(double rebate=1.0):moneyRebate(rebate){} virtual double acceptCash(double money) { return money*moneyRebate; } ~CashRebate(void); private: double moneyRebate; };
#pragma once //满多少减多少的情况 #include "cashsuper.h" class CashReturn : public CashSuper { public: CashReturn(double condition=0.0,double returns =0.0):moneyCondition(condition),moneyReturn(returns){} virtual double acceptCash(double money) { double result = money; if(money>=moneyCondition) result = money-(money/moneyCondition)*moneyReturn; return result; } ~CashReturn(void); private: double moneyCondition; double moneyReturn; };
#pragma once #include"CashSuper.h" #include"CashNormal.h" #include"CashRebate.h" #include"CashReturn.h" #include<string> class CashFactory { public: static CashSuper* createCashAccept(int type) { CashSuper *cs=NULL; switch(type) { case 1: cs = new CashNormal(); break; case 2: cs = new CashReturn(300,100); break; case 3: cs = new CashRebate(0.8); break; } return cs; } CashFactory(void); ~CashFactory(void); };
调用:
#include "stdafx.h" #include <iostream> #include "cashFactory.h" #include "CashSuper.h" using namespace std; int _tmain(int argc, _TCHAR* argv[]) { CashSuper *ptr; ptr=CashFactory::createCashAccept(1); cout<<ptr->acceptCash(200)<<endl<<endl; CashSuper *ptr2; ptr2=CashFactory::createCashAccept(2); cout<<ptr2->acceptCash(600)<<endl; cout<<ptr2->acceptCash(200)<<endl<<endl; CashSuper *ptr3; ptr3=CashFactory::createCashAccept(3); cout<<ptr3->acceptCash(600)<<endl<<endl; return 0; }
输出的结果为:
200
400
200
400
标签:style blog class code java javascript color get string int rgb
原文地址:http://www.cnblogs.com/crazycodehzp/p/3701310.html