int main()
{
    //客户端调用例子
    
    //客户端只需依赖COperator的接口类和工厂类,而无法知道具体的实现类
    //实现了客户端和具体实现类之间的解耦
    CFactory* ft= new CDivFactory(); //除法工厂
    COperator* oper =  ft->createOperator(); 
    oper->setFirst(1);
    oper->setSecond(2);
    
    printf("%f + %f = %f\n", oper->getFirst(),oper->getSecond(),oper->getResult());
    
    delete oper;
    delete ft;
    
    return 0;
}