The class definition of a binary tree class is given below. It contains an attribute called root that represents the root of a tree. It has a constructor that sets the root to NULL. There are also other methods that manipulates the tree. These methods are findLongestLength(), NumOfNodesDivisibleBy3(), searchForAnElement() and printPreOrder(). The constructor is already implemented. You are required to implement the other four methods.

#include #include using namespace std; //--------------------------------------------

class Node; typedef Node* NodePtr;

class Node { public: int number; NodePtr left; NodePtr right; Node(){number=0; left=right=NULL;} Node(int n){number=n; left=right=NULL;} }; //----------------------------------------------

class tree { public: NodePtr root; tree(){root=NULL;}; int NumOfNodesDivisibleBy3(NodePtr root); int findLongestLength(NodePtr root); int searchForAnElement(NodePtr root, int key); int printPreOrder(NodePtr root); };