C ++循环依赖

Question

I have an object class, and an exception class derives from it. Now I want a method of object class throw an exception object but run into endless "base class not defined" and "incomplete type" problems. Is this even possible?

Thanks.

Code:

class object
{

public:
    virtual ~object(){ }

    virtual bool equals(){ throw new exception; }
    virtual int getHash(){ throw new exception; }
    virtual void getType(){ throw new exception; }
};

class exception :
    public object
{
private:
public:
    exception();
    virtual ~exception();
    virtual const char* info();
};

Answer 1

Don't define the member function in the class. Define it after the two classes have been defined.

Answer 2

在这种特定情况下，只需将类object的实现放在单独的cpp文件中，只在头中留下声明。

Answer 3

Do you need the exception class to inherit from the object class? You can define the exception class before the object class in your header file if you don't want separate cpp files.

    class exception {  
        private:
        public:
            exception();
            // rest of your code
    };

    class object {
        public:
            virtual ~object() {}
            virtual bool equals() { throw exception(); }
            // rest of your code
    };