查看对象是什么类 [英] Seeing what class an object is

问题描述

如果我在C ++中有一个指向基类A的指针，我怎么能在我的代码中告诉该指针是到派生类B或C的呢?

If I have a pointer to a base class A in C++, how would I be able to tell in my code that the pointer is to a derived class B or C?

推荐答案

假定基类A是多态的(即它至少具有一个虚函数)，则可以使用dynamic_cast.给出A* ap;:

Assuming the base class A is polymorphic (i.e. it has at least one virtual function), you can use dynamic_cast. Given an A* ap;:

if (B* bp = dynamic_cast<B*>(ap)) {
    // the object is a B
}
else if (C* cp = dynamic_cast<C*>(ap)) {
    // the object is a C
}

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