Incomplete Type

Question

I\'m getting a incomplete type error for the \'next\' and \'previous\' variables. I\'m not sure what I am doing wrong because I am very rusty on writing classes in C++. An

Answer 1

it would appear that your trying to impliment a "linked list"

The structure of a linked is that next & previous "points" (*) and is not actually another node as Andre states.

http://www.cplusplus.com/doc/tutorial/pointers/ may help clarify.

class LinearNode
{
//...snip
//returns the next node in the set.
LinearNode* getNext();
//returns the previous node in the set
LinearNode* getPrevious();

//...snip
private: 
    LinearNode * next;
    LinearNode * previous;
};

So in the implementation file:

//returns the next element in the structure
LinearNode* LinearNode::getNext()
{
    return next; // now a poiner
}//ends getNext function

//returns previous element in structure
LinearNode*  LinearNode::getPrevious()
{
    return previous; // now a poiner
}//ends getPrevious function

//sets the next variable for the node
void LinearNode::setNext(LinearNode* node) //pointer in, void out
{
    next = node
}//ends the setNext function

//sets previous for the node
void LinearNode::setPrevious(LinearNode* node)//pointer in, void out
{
    previous = node;
}//ends the setPrevious function

so main looks like:

int main()
{
    LinearNode node1, node2, move;
    node1.setElement(1);
    node2.setElement(2);

    node2.setNext(&node1); // give the address of node to the next pointer (&)
    node1.setPrevious(&node2); // give the address of node to the next pointer (&)

    move = node2;

    while(move.getNext() != NULL)
        cout << move.getElement() << endl;

}

I don't know what the while loop's trying to do though! if - perhaps?

Also as Nicklamort states all your class functions need to have a return type, except in the case of void.