我可以在不使用虚函数的情况下获得多态行为吗?

2022-01-24 00:00:00 function polymorphism overriding c++ virtual

由于我的设备，我无法使用虚拟功能.假设我有:

Because of my device I can't use virtual functions. Suppose I have:

class Base
{
    void doSomething() { }
};

class Derived : public Base
{
    void doSomething() { }
};

// in any place
{
    Base *obj = new Derived;
    obj->doSomething();
}

obj->doSomething() 将只调用 Base::doSomething()

Base *obj有没有办法调用Derived的doSomething?

我知道我可以在 Base 的 doSomething() 之前放置一个 virtual 来解决问题，但我受限于我的设备，编译器不支持.

I know I can just put a virtual before doSomething() of Base it solve the problem, but I'm limited by my device, the compiler doesn't support it.

推荐答案

您可以将基类指针向下转换为派生类并调用函数.

You could down cast the base class pointer to the derived class and call the function. 

Base* obj = new Derived;
Derived* d = static_cast<Derived*>( obj ); 
d->doSomething();

由于 doSomething() 没有被声明为 virtual，你应该得到派生的实现.

Since doSomething() is not declared virtual, you should get the derived implementation.

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