c++写一个计算器程序

Question

用面向对象方法设计一个计算器控制台程序。

1.1设计一个父类Operation, 数据成员包含两个操作数m_numberA，m_numberB。 成员函数包括set(),get()函数设置操作数的值，虚函数GetResult()用于输出结果。

1.2分别设计派生类 OperationAdd，OperationSub，OperationMul， OperationDiv实现加减乘除操作,注意除法操作除数不能为0。

1.3派生类统一继承自父类Operation, 重写虚函数GetResult()输出操作后的结果。

1.4 OperationFactory类已经写好，可以直接使用。
class OperationFactory {

public:

static Operation * CreateOperate(char oper)

{

   Operation * poper = NULL;

                 switch (oper) 

                    {

                               case '+':

                          poper = new OperationAdd;

                             break;

                               case '-':

                             poper = new OperationSub;

                             break;

                               case '*':

                                      poper = new OperationMul;

                                      break;

                               case '/':

                                      poper = new OperationDiv;

                                      break;

                     }

        return poper;

   }

};

int main()

{

   int flag = 1;

   while (flag)

   {

          cout << "input A:";

          double numA;

          cin >> numA;

          cout << "input operator:";

          char oper;

          cin >> oper;

          cout << "input B:";

          double numB;

          cin >> numB;

          Operation* poper = OperationFactory::CreateOperate(oper);

          poper->SetNumA(numA);

          poper->SetNumB(numB);

          cout << poper->GetNumA() << ' ' << oper << ' ' << poper->GetNumB() << " = " << poper->GetResult() << endl;

          cout << "是否需要继续: (0/1)";

          cin >> flag;

   }

   return 0;

}

Answer 1

class Operation
{
    double m_numberA,m_numberB;
public:
    double GetNumA() {return m_numberA;}
    double GetNumB() {return m_numberB;}
    void SetNumA(double A) {m_numberA = A;}
    void SetNumB(double B) {m_numberB = B;}
    virtual double GetResult() {return 0;}
};

class OperationAdd : public Operation
{
public:
    virtual double GetResult() {return GetNumA() + GetNumB();}
};

class OperationSub : public Operation
{
public:
    virtual double GetResult() {return GetNumA() - GetNumB();}
};

class OperationMul : public Operation
{
public:
    virtual double GetResult() {return GetNumA() * GetNumB();}
};

class OperationDiv : public Operation
{
public:
    virtual double GetResult() { if(GetNumB() == 0) return 0; return GetNumA() / GetNumB();}
};


class OperationFactory {
public:

static Operation * CreateOperate(char oper)

{

   Operation * poper = NULL;
 
                 switch (oper) 
 
                    {
 
                               case '+':
 
                          poper = new OperationAdd;
 
                             break;
 
                               case '-':
 
                             poper = new OperationSub;
 
                             break;
 
                               case '*':
 
                                      poper = new OperationMul;
 
                                      break;
 
                               case '/':
 
                                      poper = new OperationDiv;
 
                                      break;
 
                     }
 
        return poper;
 
   }
};

int main()

{
   int flag = 1;
 
   while (flag)
 
   {
 
          cout << "input A:";
 
          double numA;
 
          cin >> numA;
 
          cout << "input operator:";
 
          char oper;
 
          cin >> oper;
 
          cout << "input B:";
 
          double numB;
 
          cin >> numB;
 
          Operation* poper = OperationFactory::CreateOperate(oper);
 
          poper->SetNumA(numA);
 
          poper->SetNumB(numB);
 
          cout << poper->GetNumA() << ' ' << oper << ' ' << poper->GetNumB() << " = " << poper->GetResult() << endl;
 
          cout << "是否需要继续: (0/1)";
 
          cin >> flag;
 
   }
 
   return 0;
}

Answer 2

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