Design pattern C + + implementation one: Simple engineering mode

Refer to the big talk design pattern and some information on the net, write down some simple design patterns, let yourself understand the beauty of these design patterns!

#ifndef operation_h#define operation_h#include<iostream>using namespace Std;class operation{protected:double OpA, Opb;public:bool SetValue (double& N, double& m); virtual double getresult () const=0;}; Class Operationadd:p ublic operation{double getresult () const;}; Class Operationsub:p ublic operation{double getresult () const;}; Class Operationmul:p ublic operation{double getresult () const;}; Class Operationdiv:p ublic operation{double getresult () const;}; Class Operationfactory{public:operation * Creatoperation (char& operate);}; BOOL Operation::setvalue (double &n, double &m) {OpA = N;OPB = M;return true;} Double Operationadd::getresult () const{double Result;result = OpA + opb;return result;} Double Operationsub::getresult () const{double result;result = Opa-opb;return result;} Double Operationmul::getresult () const{double result;result = OpA * Opb;return result; Double Operationdiv::getresult () const{if (OpB = = 0) {cout << "OpB in Operationdiv can ' t is zero.\n"; return 0.00000001;} Double result;result = Opa/opb;return result;} Operation * Operationfactory::creatoperation (char& operate) {operation * Oper = Null;switch (operate) {case (' + '): O per = new Operationadd;break;case ('-'): Oper = new Operationsub;break;case (' * '): Oper = new Operationmul;break;case ('/'): Oper = new Operationdiv;break;default:break;} return Oper;} #endif

#include "operation.h" int main () {double NumA, numb;char op;operation * oper;operationfactory opfa;cout << "please Enter the numbers and operation (A op B) "; while (Cin>>numa&&cin>>op&&cin>>numb) {Oper = Opfa.creatoperation (OP); Oper->setvalue (NUMA, NumB) cout << "The result of" << NumA << op << NumB << "=" << oper->getresult () << endl;cout << "Please enter the numbers and operation (A op B) ";} return 0;}

Design pattern C + + implementation one: Simple engineering mode