C 继承添加操作员

Question

我想在派生的类中制作" "运算符时，我会有一些问题。我的基课上已经有一个" " Oparator。

class Base{
    //Some data
public: 
    //Some other function
    Base operator+(const Base& rhs_s) const ;
    Base operator+(char rhs_c) const { return *this + Base(rhs_c);}
    //Some other function
};

class Derived :public Base{
public: 
    Derived () :Base("") {}
    Derived (char c) :Base(c) {}
    Derived (const char* c) :Base(c) {}
    Derived operator+(const Derived& s) const {
        return Derived(*this) + Derived(s);
   }

所以我不能添加两个变量，其中"派生 'c'"

我感谢您的帮助

Answer 1

使用您的代码，我可以做到这一点：

Derived d{'c'};
const Derived d2 = d + 'C';

您在评论中的示例不同：

const Base d("hello");
Derived b;
b = d + 'C';

上面的代码不会编译，因为将返回基本对象，该对象无法隐式升起到派生类型。例如：

Derived d;
Base b = d; // This is fine because you are going from a more specific type to a less specific one
Derived d2 = b; // This is not okay unless you explicitly define an assignment/constructor for Derived that takes a Base object