Question

I have C# background and been working with C# for so many years.. Recently, I’m learning C++ and having some difficulties..

Basically, I’m trying to create the linked link class as below. I want to use my class as a data in struct node.

How can I fix this in C++? Thanks.

But it said that i can’t use like that.

class Polynomial{
    public:
        Polynomial(pair<double, int>);  

        void add(Polynomial);
        Polynomial multiply(Polynomial);
        void print();
    private:
         struct node
         {
            Polynomial data;
            node *link;
         }*p;
};

Answer 1

Your node struct contains a member variable of type Polynominal, but since node itself is declared inside Polynominal, the declaration of Polynominal isn’t complete at that point.

I get the impression that you assume classes in C++ to work just like C#, but they don’t. C++ isn’t garbage-collected, and it doesn’t automatically manage references for you when you use classes. A class in C++ behaves more like a struct in C#, and when you pass or declare it like in your example, it gets copied by value.

Another thing: C++ comes with STL, which contains a range of templates for all sorts of things, including a nice linked list (std::list).