C++

Question

我在覆盖 operator= 重载时遇到问题。当我尝试使用运算符将一个 Derived 对象复制到另一个时，它完全避免了 Derived 覆盖，而只是调用 Base operator= :

class Base
{
    public:
        virtual Base* clone() const;
    protected:
        virtual void operator=(const Base& copyBase);
}
class Derived : public Base
{
    public:
        Derived* clone() const;
    private:
        void operator=(const Base& copyBase) override;
}

Derived* Derived::clone() const
{
    Derived* clone = new (std::nothrow) Derived();
    if(clone)
    {
        *clone = *this;    // <--- Base operator= get's called
    }
    return clone;
}

Derived::clone() 被正确调用，但不是调用 Derived::operator=，而是跳转到 Base::operator=，我似乎无法弄清楚原因。 virtual operator= 有什么特别之处还是我在做一些愚蠢的事情？

Answer 1

您忘记的是，无论您编写了什么，您仍然会得到编译器提供的特定于派生的复制赋值运算符。由于它比基础-class 版本更匹配，因此调用默认版本。

C++ - virtual operator= 从 Derived 实例在 Base class 上被调用？

C++ - virtual operator= being called on Base class from Derived instance?

polymorphism

virtual

operator-overloading