设计模式--简单工厂模式实例-优快云博客

本文介绍了一个使用C++实现的简单计算器程序，该程序通过工厂模式动态创建加、减、乘、除四种运算对象。用户可以输入两个数字，程序将根据所选操作返回计算结果。

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main.cpp:

#include <iostream>

#include <string>
using namespace std;

#include "operation.h"
#include "operationAdd.h"
#include "operationSub.h"
#include "operationMul.h"
#include "operationDiv.h"
#include "operationFactory.h"

int main()
{
   Factory *q = new Factory();

   //class Add
   cout<<"class Add example:\n";
    operation *p_add= q->create(1);
    double number_A, number_B;
    cout<<"please input number_A value:";
    cin>>number_A;
   p_add->setValueA(number_A);
   cout<<"please input number_B value:";
    cin>>number_B;
   p_add->setValueB(number_B);
    p_add->getResult();
   delete p_add;
   p_add = NULL;

   //class Sub
   cout<<"class Sub example:\n";
   operation *p_sub = q->create(2);
    cout<<"please input number_A value:";
    cin>>number_A;
   p_sub->setValueA(number_A);
   cout<<"please input number_B value:";
    cin>>number_B;
   p_sub->setValueB(number_B);
    p_sub->getResult();
   delete p_sub;
   p_sub = NULL;

   //class Mul
   cout<<"class Mul example:\n";
   operation *p_mul = q->create(3);
    cout<<"please input number_A value:";
    cin>>number_A;
   p_mul->setValueA(number_A);
   cout<<"please input number_B value:";
    cin>>number_B;
   p_mul->setValueB(number_B);
    p_mul->getResult();
   delete p_mul;
   p_mul = NULL;

   //class Div
   cout<<"class Div example:\n";
   operation *p_Div = q->create(4);
    cout<<"please input number_A value:";
    cin>>number_A;
   p_Div->setValueA(number_A);
   cout<<"please input number_B value:";
    cin>>number_B;
   p_Div->setValueB(number_B);
    p_Div->getResult();
   delete p_Div;
   p_Div = NULL;

    return 0;
}

operation.h :

class operation
{
public:
   virtual void getResult() = 0;
   virtual void setValueA(double m_r) = 0;
   virtual void setValueB(double m_r) = 0;
};

operationAdd.h :

class Add:public operation
{
private:
    double number_A;
   double number_B;
public:
    //Add(double r);
    void getResult();
   void setValueA(double m_r);
   void setValueB(double m_r);
};

void Add::getResult()
{
   double result;
   result = number_A + number_B;
    cout<<"The result is :"<<result<<endl;
}
void Add::setValueA(double m_r)
{
   number_A= m_r;
}

void Add::setValueB(double m_r)
{
   number_B= m_r;
}

operationSub.h :

class Sub:public operation
{
private:
    double number_A;
   double number_B;
public:
    //Add(double r);
    void getResult();
   void setValueA(double m_r);
   void setValueB(double m_r);
};

void Sub::getResult()
{
   double result;
   result = number_A - number_B;
    cout<<"The result is :"<<result<<endl;
}
void Sub::setValueA(double m_r)
{
   number_A= m_r;
}

void Sub::setValueB(double m_r)
{
   number_B= m_r;
}

operationMul.h :

class Mul:public operation
{
private:
    double number_A;
   double number_B;
public:
    //Add(double r);
    void getResult();
   void setValueA(double m_r);
   void setValueB(double m_r);
};

void Mul::getResult()
{
   double result;
   result = number_A * number_B;
    cout<<"The result is :"<<result<<endl;
}
void Mul::setValueA(double m_r)
{
   number_A= m_r;
}

void Mul::setValueB(double m_r)
{
   number_B= m_r;
}

operationDiv.h :

class Div:public operation
{
private:
    double number_A;
   double number_B;
public:
    //Add(double r);
    void getResult();
   void setValueA(double m_r);
   void setValueB(double m_r);
};

void Div::getResult()
{
   double result;
   if (number_B == 0)
   {
       cout<<"The div data is not zero!!\n";
       return;
   }
   result = number_A / number_B;
    cout<<"The result is :"<<result<<endl;
}
void Div::setValueA(double m_r)
{
   number_A= m_r;
}

void Div::setValueB(double m_r)
{
   number_B= m_r;
}

operationFactory.h :

class Factory
{
   public:
   operation* create(int type)
   {
       switch (type)
       {
       case 1:
           return new Add();
       case 2:
           return new Sub();
       case 3:
           return new Mul();
       case 4:
           return new Div();
       default:
           return NULL;
       }
   }
};

所有的.h文件跟.cpp文件一样！！

运行结果如下：

ngnsvr9 [** NONE **]/home/xionghailong/mode $ g++ main.cpp -o main

ngnsvr9 [** NONE **]/home/xionghailong/mode $ ./main
class Add example:
please input number_A value:1
please input number_B value:2
The result is :3
class Sub example:
please input number_A value:3
please input number_B value:4
The result is :-1
class Mul example:
please input number_A value:2
please input number_B value:3
The result is :6
class Div example:
please input number_A value:2
please input number_B value:3
The result is :0.666667