BinaryTree.h

#ifndef BINARYTREE_H
#define BINARYTREE_H
#include <iostream>
using namespace std;

// This class is a template class that creates a binary
// tree that can hold values of any data type. It has
// functions to insert a node, delete a node, display the
// tree In Order, Pre Order and Post Order, search for a
// value, count the number of total nodes, left nodes,
// and a function to determine the height of the tree.

template <class T>
class BinaryTree
{
private:
    struct TreeNode
    {
        T value;            // The value in the node
        TreeNode *left;     // Pointer to left child node
        TreeNode *right;    // Pointer to right child node
    };

    TreeNode *root;         // Pointer to the root node

    // Private member functions
    void insert(TreeNode *&, TreeNode *&);
    void destroySubTree(TreeNode *);
    void deleteNode(T, TreeNode *&);
    void makeDeletion(TreeNode *&);
    void displayInOrder(TreeNode *) const;
    void displayPreOrder(TreeNode *) const;
    void displayPostOrder(TreeNode *) const;
    int counter(TreeNode *);
    int leafCounter(TreeNode *);
    int height(TreeNode *);

public:
    // Constructor
    BinaryTree()
    { root = NULL; }

    // Destructor
    ~BinaryTree()
    { destroySubTree(root); }

    // Binary tree operations
    void insertNode(T);
    bool searchNode(T);
    void remove(T);

    void displayPreOrder() const
    { displayPreOrder(root); }

    void displayInOrder() const
    { displayInOrder(root); }

    void displayPostOrder() const
    { displayPostOrder(root); }

    // Node counter
    int counter()
    {
        int n = counter(root);
        return n;
    }

    // Leaf counter
    int leafCounter()
    {
        int leaf = leafCounter(root);
        return leaf;
    }

    // Height of the tree
    int height()
    {
        int h = height(root);
        return h;
    }
};

//*********************************************************
// insert function accepts a TreeNode pointer and a       *
// pointer to a node. The function inserts the node into  *
// the tree pointer to by the TreeNode pointer. This      *
// function is call recursively.                          *
//*********************************************************
template <class T>
void BinaryTree<T>::insert(TreeNode *&nodePtr, TreeNode *&newNode)
{
    if (nodePtr == NULL)
        nodePtr = newNode;              // Insert the node
    else if (newNode->value < nodePtr->value)
        insert(nodePtr->left, newNode); // Search the left branch
    else
        insert(nodePtr->right, newNode);// Search the right branch
}

//*********************************************************
// insertNode creates anew node to hold num as its value  *
// and passes it to the insert function.                  *
//*********************************************************
template <class T>
 void BinaryTree<T>::insertNode(T item)
 {
     TreeNode *newNode;     // Pointer to a new node

     // Create anew node and store num in it
     newNode = new TreeNode;
     newNode->value = item;
     newNode->left = newNode->right = NULL;

     // Insert the node
     insert(root, newNode);
 }

//**********************************************************
// destroySubTree is called by the destructor. It deletes  *
// all nodes in the tree.                                  *
//**********************************************************
template <class T>
void BinaryTree<T>::destroySubTree(TreeNode *nodePtr)
{
     if (nodePtr)
     {
         if (nodePtr->left)
             destroySubTree(nodePtr->left);
         if (nodePtr->right)
             destroySubTree(nodePtr->right);
         delete nodePtr;
     }
}

//**********************************************************
// searchNode determines if a value is present in the tree.*
// If so, the function returns true. Otherwise it returns  *
// false.
//**********************************************************
template <class T>
bool BinaryTree<T>::searchNode(T item)
{
    TreeNode *nodePtr = root;

    while (nodePtr)
    {
        if (nodePtr->value == item)
            return true;
        else if (item < nodePtr->value)
            nodePtr = nodePtr->left;
        else
            nodePtr = nodePtr->right;
    }
    return false;
}

//*********************************************************
// remove calls deleteNode to delete the node whode value *
// member is the same as num                              *
//*********************************************************
template <class T>
void BinaryTree<T>::remove(T item)
{
    deleteNode(item, root);
}

//*********************************************************
// deleteNode deletes the node whose value member is the  *
// same as num                                            *
//*********************************************************
template <class T>
void BinaryTree<T>::deleteNode(T item, TreeNode *&nodePtr)
{
    if (item < nodePtr->value)
        deleteNode(item, nodePtr->left);
    else if (item > nodePtr->value)
        deleteNode(item, nodePtr->right);
    else
        makeDeletion(nodePtr);
}

//*********************************************************
// makeDeletion takes a reference to apointer to the node *
// that is to be deleted. The node is removed and the     *
// branches of the tree below the node are reattached     *
//*********************************************************
template <class T>
void BinaryTree<T>::makeDeletion(TreeNode *&nodePtr)
{
    // Define a temporary pointer to use in reattaching
    // the left subtree
    TreeNode *tempNodePtr;

    if (nodePtr == NULL)
        cout << "Cannot delete empty node.\n";
    else if (nodePtr->right == NULL)
    {
        tempNodePtr = nodePtr;
        nodePtr = nodePtr->left;    // Reattach the left child
        delete tempNodePtr;
    }
    else if (nodePtr->left == NULL)
    {
        tempNodePtr = nodePtr;
        nodePtr = nodePtr->right;   // Reattach the right child
        delete tempNodePtr;
    }

}
//*********************************************************
// The displayInOrder function displays the values in the *
// subtree pointed to by nodePtr, via inorder traversal   *
//*********************************************************
template <class T>
void BinaryTree<T>::displayInOrder(TreeNode *nodePtr) const
{
    if (nodePtr)
    {
        displayInOrder(nodePtr->left);
        cout << nodePtr->value.getEmpID() << " "
                     << getEmpName() << endl;
        displayInOrder(nodePtr->right);
    }
}
//*********************************************************
// The displayPreOrder function displays the values in the*
// subtree pointed to by nodePtr, via Preorder traversal  *
//*********************************************************
template <class T>
void BinaryTree<T>::displayPreOrder(TreeNode *nodePtr) const
{
    if (nodePtr)
    {
        cout << nodePtr->value << endl;
        displayInOrder(nodePtr->left);
        displayInOrder(nodePtr->right);
    }
}
//*********************************************************
// displayPostOrder function displays the values in the   *
// subtree pointed to by nodePtr, via Postorder traversal *
//*********************************************************
template <class T>
void BinaryTree<T>::displayPostOrder(TreeNode *nodePtr) const
{
    if (nodePtr)
    {
        displayInOrder(nodePtr->left);
        displayInOrder(nodePtr->right);
        cout << nodePtr->value << endl;
    }
}

//*********************************************************
// counter counts the number of nodes the tree has        *
//*********************************************************
template <class T>
int BinaryTree<T>::counter(TreeNode *nodePtr)
{
    if (nodePtr == NULL)
        return 0;
    else
        return counter(nodePtr->left) +1+ counter(nodePtr->right);
}

//*********************************************************
// leafCounter counts the number of leaf nodes in the tree*
//*********************************************************
template <class T>
int BinaryTree<T>::leafCounter(TreeNode *nodePtr)
{
    if (nodePtr == NULL)
        return 0;
    else if (nodePtr->left == NULL && nodePtr->right == NULL)
        return 1;
    else
        return leafCounter(nodePtr->left) + leafCounter(nodePtr->right);
}

//*********************************************************
// height returns the height of the tree                  *
//*********************************************************
template <class T>
int BinaryTree<T>::height(TreeNode *nodePtr)
{

    if(nodePtr == NULL)
        return -1;
    if (height(nodePtr->left) <= height(nodePtr->right))
        return (height(nodePtr->right) +1);
    else
        return (height(nodePtr->left) +1);

}
#endif
EmployeeInfo.h

#ifndef EMPLOYEEINFO_H
#define EMPLOYEEINFO_H
#include <string>
using namespace std;

// This class has two data members to hold the employee ID
// and the name of the employee.

class EmployeeInfo
{
private:
    int empID;      // To hold employee ID number
    string empName; // To hold employee name

public:
    // Default Constructor
    EmployeeInfo();

    // Constructor
    EmployeeInfo(int, string);

    // Mutators
    void setEmpID(int);
    void setEmpName(string);

    // Accessors
    int getEmpID();
    string getEmpName();

    bool operator < (const EmployeeInfo &e)
        {
        if (empID < e.empID)
            return true;
        if (empName < e.empName)
            return true;
        return false;
        }
};
#endif
#include "EmployeeInfo.h"

//*********************************************************
// Default constructor intializes the data members        *
//*********************************************************
EmployeeInfo::EmployeeInfo()
{
    empID = 0;
    empName = "";
}

//*********************************************************
// Constructor sets the data members                      *
//*********************************************************
EmployeeInfo::EmployeeInfo(int ID, string name)
{
    empID = ID;
    empName = name;
}

//*********************************************************
// setEmpID stores the employee ID number                 *
//*********************************************************
void EmployeeInfo::setEmpID(int ID)
{
    empID = ID;
}

//*********************************************************
// setEmpName stores the full name of the employee        *
//*********************************************************
void EmployeeInfo::setEmpName(string name)
{
    empName = name;
}

//*********************************************************
// getEmpID returns the employee ID number                *
//*********************************************************
int EmployeeInfo::getEmpID()
{
    return empID;
}

//*********************************************************
// getEmpName returns the full name of the employee       *
//*********************************************************
string EmployeeInfo::getEmpName()
{
    return empName;
}
Main

#include "EmployeeInfo.h"
#include "BinaryTree.h"
#include <iostream>
using namespace std;

int main()
{

    // Create an instance of BinaryTree
    BinaryTree<EmployeeInfo> tree;

    // Create an EmployeeInfo object
    EmployeeInfo info;
    EmployeeInfo emp1(1021, "John Williams");
    EmployeeInfo emp2(1057, "Bill Witherspoon");

    // Store the information
    info.setEmpID(1021);
    info.setEmpID(1057);

    info.setEmpName("John Williams");
    info.setEmpName("Bill Witherspoon");

    tree.insertNode(emp1);
    tree.insertNode(emp2);

    // Display in order
    tree.displayInOrder();
}