【大话设计模式】——简单工厂模式

简单工厂模式：

UML图


代码：
Operation：

#include "Operation.h"
#include <iostream>

Operation::Operation(void)
{
}

Operation::~Operation(void)
{
}

double Operation::GetResult()
{
    return 0;
}

double Operation::getNum1()
{
    return num_1;
}
double Operation::getNum2()
{
    return num_2;
}
void Operation::setNum1(double data)
{
    num_1 = data;
}
void Operation::setNum2(double data)
{
    num_2 = data;
}

ADD:

ADD::ADD(void)
{
}

ADD::~ADD(void)
{
}
double ADD::GetResult()
{
    return Operation::getNum1()+Operation::getNum2();
}

SUB:

MINUS::MINUS(void)
{
}

MINUS::~MINUS(void)
{
}
double MINUS::GetResult()
{
    return Operation::getNum1()-Operation::getNum2();
}

Factory:

Factory::Factory(void)
{
}

Factory::~Factory(void)
{
}
Operation* Factory::CreateFactory(char cal)
{
    Operation* op;
    switch(cal)
    {
    case '+':
            op = new ADD();
            break;
    case '-':
            op = new MINUS();
            break;
    }
    return op
}

主函数：

int main()
{
    double a,b;
    char op;
    cin>>a>>b;
    cin>>op;

    Factory fac;
    Operation* test = fac.CreateFactory(op);
    test->setNum1(a);
    test->setNum2(b);
    cout<<test->GetResult()<<endl;
}