How to return nested class pointer from method?

Question

I have two classes: Database and Node as a nested class, is it possible to have a method of Node that will return a Node*?

I tried to set the method nextNode return type as Node* but I get a compilation error: 'Node' does not name a type

Databse.h

class Database
{
    public:
        Database();
        Database& operator+=(const Client&);
        ~Database();
    private:
        class Node //node as nested class
        {
            public:
            Node(); //ctor
            void setHead(Client*&); //add head node
            Node* nextNode(Node*&); //return new node from the end of he list
            private:
            Client* data; //holds pointer to Client object
            Node* next; //holds pointer to next node in list
        };

        Node *head; //holds the head node
};

nextNode method declaration in Databse.cpp:

Node* Database::Node::nextNode(Node*& start)
{
....
....
    return current->next;
}

Thanks.

score 7 · Accepted Answer · answered Aug 21 '14 at 12:57

7

Node is nested in Database, so you need the scope for the return type:

DataBase::Node* Database::Node::nextNode(Node*& start)
^^^^^^^^^^

The parameter is already in scope, so you may leave it as is.

answered Aug 21 '14 at 12:57

juanchopanza

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Thanks! Can you direct me to some good documentation about nested classes? – Medvednic Aug 21 '14 at 13:01
2

@Medvednic I would go through some of the [books in this list](http://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list). – juanchopanza Aug 21 '14 at 13:05

score 5 · Answer 2 · answered Aug 21 '14 at 13:02

5

Additionally to juanchopanza's answer, C++11's trailing return type allows you to declare it in-scope :

auto Database::Node::nextNode(Node*& start) -> Node* {
    // ...
}

answered Aug 21 '14 at 13:02

Quentin

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How to return nested class pointer from method?

2 Answers2