設計模式複習-工廠方法模式
相對于簡單工廠，工廠方法是把算法類的執行個體化延遲到了調用者那去做，調用者根據自己的需要，自己執行個體化相關的工廠并且生産相關算法。這麼做是因為簡單工廠是不滿足OCP的，因為如果想添加新的算法，就得去改工廠函數裡面的那個switch，這樣容易在增加新的功能時引入新問題，而工廠方法不會導緻這個問題，在算法擴充的時候滿足OCP，不需要改之前原有的東西，直接往上加就行了。
//FactoryMode.h
#pragma once
//抽象算法接口
class CinterfaceAlgorithm {
public:
virtual bool GetValue(const int &nNumberA, const int &nNumberB, int &nNumberAns) = 0;
};
class CAddition : public CinterfaceAlgorithm {
public:
bool GetValue(const int &nNumberA, const int &nNumberB, int &nNumberAns) {
nNumberAns = nNumberA + nNumberB;
return true;
}
};
class CSubtraction : public CinterfaceAlgorithm {
public:
bool GetValue(const int &nNumberA, const int &nNumberB, int &nNumberAns) {
nNumberAns = nNumberA - nNumberB;
return true;
}
};
class CMultiplication : public CinterfaceAlgorithm {
public:
bool GetValue(const int &nNumberA, const int &nNumberB, int &nNumberAns) {
nNumberAns = nNumberA * nNumberB;
return true;
}
};
class CDivision : public CinterfaceAlgorithm {
public:
bool GetValue(const int &nNumberA, const int &nNumberB, int &nNumberAns) {
if (nNumberB == 0) {
return false;
}
nNumberAns = nNumberA / nNumberB;
return true;
}
};
//工廠接口
class CinterfaceFactory {
public:
virtual CinterfaceAlgorithm * GetFactoryBody() = 0;
};
class CAdditionFactory : public CinterfaceFactory {
CinterfaceAlgorithm * GetFactoryBody(){
return new CAddition();
}
};
class CSubtractionFactory : public CinterfaceFactory {
CinterfaceAlgorithm * GetFactoryBody() {
return new CSubtraction();
}
};
class CMultiplicationFactory : public CinterfaceFactory {
CinterfaceAlgorithm * GetFactoryBody() {
return new CMultiplication();
}
};
class CDivisionFactory : public CinterfaceFactory {
CinterfaceAlgorithm * GetFactoryBody() {
return new CDivision();
}
};
#include "stdafx.h"
#include "FactoryMode.h"
#include <iostream>
using namespace std;
int main() {
CinterfaceAlgorithm *pHashMemoryAlgorithm[10] = { 0 };
CinterfaceFactory * pHashMemoryFactory[10] = { 0 };
int nAlgorithmId = -1, nFactoryId = -1, nAns = 0;
pHashMemoryFactory[++nFactoryId] = new CAdditionFactory();
pHashMemoryAlgorithm[++nAlgorithmId] = pHashMemoryFactory[nFactoryId]->GetFactoryBody();
pHashMemoryFactory[++nFactoryId] = new CSubtractionFactory();
pHashMemoryAlgorithm[++nAlgorithmId] = pHashMemoryFactory[nFactoryId]->GetFactoryBody();
pHashMemoryFactory[++nFactoryId] = new CMultiplicationFactory();
pHashMemoryAlgorithm[++nAlgorithmId] = pHashMemoryFactory[nFactoryId]->GetFactoryBody();
pHashMemoryFactory[++nFactoryId] = new CDivisionFactory();
pHashMemoryAlgorithm[++nAlgorithmId] = pHashMemoryFactory[nFactoryId]->GetFactoryBody();
for (int nPoit = 0; nPoit <= nAlgorithmId; nPoit++) {
if (pHashMemoryAlgorithm[nPoit] != NULL && pHashMemoryAlgorithm[nPoit]->GetValue(1, 5, nAns)) {
cout << nAns << endl;
}
else {
cout << "Error" << endl;
}
}
for (int nPoit = 0; nPoit <= nAlgorithmId; nPoit++) {
delete pHashMemoryAlgorithm[nPoit];
delete pHashMemoryFactory[nPoit];
}
//getchar();
return 0;
}