简单工厂模式

来源：互联网发布：pdf转换ppt软件编辑：程序博客网时间：2024/06/09 20:57

看了<<大话设计模式>>, 照着写了一个简单工厂模式的计算器, 慢慢来, 不急.

#include <iostream>#include <stdexcept>using namespace std;class Operation{public:virtual float Operating() = 0;public:float numberleft;float numberright;};class OperationAdd : publicOperation{public:float Operating(){return (numberleft + numberright);}};class OperationSub : public Operation{public:float Operating(){return (numberleft - numberright);}};class OperationMul : public Operation{public:float Operating(){return (numberleft * numberright);}};class OperationDiv : public Operation{public:float Operating(){if (numberright == 0)   //抛出异常throw std::out_of_range("参数异常: 除法右值不能为0");return (numberleft / numberright);}};// 运算符工厂class OperationFactory{public:OperationFactory(){op = NULL;}void Operating(float numberleft, char operate, float numberright){switch(operate){case ('+'):op = new OperationAdd;break;case ('-'):op = new OperationSub;break;case ('*'):op = new OperationMul;break;case ('/'):op = new OperationDiv;break;default:throw std::out_of_range("参数异常: 没有输入正确的运算符");break;}op->numberleft = numberleft;op->numberright = numberright;}float GetResult(){return op->Operating();}private:Operation * op;};void Operate(){float numberA;float numberB;char operate;cout << "请输入数字A :";cin >> numberA;cout << "请输入运算符:";cin >> operate;cout << "请输入数字B :";cin >> numberB;OperationFactory *opef = new OperationFactory;opef->Operating(numberA, operate, numberB);cout << "结果是:" << opef->GetResult() << endl;}int main(){//Operate();try{Operate();}catch (exception &e) // 异常要用引用收{cout << e.what() << endl;}catch (...){}system("pause");return 0;}

阅读全文

0 0