Can't get pointer to point to a node

Question

I am trying to create my own Binary Tree data structure.

I am using a BinaryNode<T> class as the leaves with a BinaryNode<T>* root to keep track of the root node.

template<class T>
class PPBinaryTree {
private:
    BinaryNode<T>* root;

public:
    PPBinaryTree();

    bool add(T Data, BinaryNode<T>* Root); 

    T* search(T Data, BinaryNode<T>* Root);  
};

Here is the implementation of the add function. No matter what I try I cannot create any new branches. The RootProbe seems to be a copy of the branch pointers so when I assign Data to it nothing changes in the branch.

The only solution I can think of is to change the line

RootProbe = (new BinaryNode<T>(Data));

to

*RootProbe = *(new BinaryNode<T>(Data));

but that just makes my program crash with an unhandled exception.

template<class T>
bool PPBinaryTree<T>::add(T Data, BinaryNode<T>* Root){
    bool isSuccessful = false;
    BinaryNode<T>* RootProbe;

    if(Root == NULL){
        Root = new BinaryNode<T>(Data);
        this->setRoot(Root);
        isSuccessful = true;
        return isSuccessful;
    }
    else{
        while(RootProbe != NULL){
            if(Data > Root->getData())
                RootProbe = Root->getRightBranch();
            else
                RootProbe = Root->getRightBranch();
        }
        RootProbe = (new BinaryNode<T>(Data));

        isSuccessful = true;
        return isSuccessful;
    }
}

Here is the BinaryNode class:

template<class S>
class BinaryNode {
private:
    S data;
    BinaryNode *leftBranch;
    BinaryNode *rightBranch;

public:
    BinaryNode(S data);

    void setData(S data);

    S getData( );

    void setLeftBranch(BinaryNode newNode);

    BinaryNode* getLeftBranch( );

    void setRightBranch(BinaryNode newNode);

    BinaryNode* getRightBranch( );
};

@Arkady _'RootProbe = (new BinaryNode(Data)); to *RootProbe = *(new BinaryNode(Data)); but that just makes my program crash with an unhandled exception.'_ — πάντα ῥεῖ, Jun 30 '14 at 10:02
possible duplicate of [What is The Rule of Three?](http://stackoverflow.com/questions/4172722/what-is-the-rule-of-three) — πάντα ῥεῖ, Jun 30 '14 at 10:07

Arkady · Answer 1 · 2014-06-30T10:03:50.563

I can guess that:

while(RootProbe != NULL){
    if(Data > Root->getData())
        RootProbe = Root->getRightBranch();
    else
        RootProbe = Root->getRightBranch();
}
RootProbe = (new BinaryNode<T>(Data));

Have to be changed, to initialize RootProbe from right and left branches. Also you forgot to set your RootProbe somewhere in the tree.

BinaryNode<T>* LastLiveProbe;
while(RootProbe != NULL){
    if(Data > Root->getData())
    {
        RootProbe = Root->getLeftBranch();
        if (RootProbe == NULL)
            LastLiveProbe->setLeftBranch(new BinaryNode<T>(Data));
        else
            LastLiveProbe = RootProbe;
    }
    else
    {
        RootProbe = Root->getRightBranch();
        if (RootProbe == NULL)
            LastLiveProbe->setRightBranch(new BinaryNode<T>(Data));
        else
            LastLiveProbe = RootProbe;
    }
}

If you don't have other problems, that should help.

Can't get pointer to point to a node

1 Answers1