Question

Data Structures Using C++:

Using C++:

Write the definition of the function, nodeCount, that returns the number of nodes in a binary tree. Add this function to the class binaryTreeType and create a program to test this function. Read the tree definitions from files.

Answer 1

Following is the Algorithmic definition of the nodeCount function

int nodeCount( TreeNode *root ) {

           // Count the nodes in the binary tree to which

           // root points, and return the answer.

        if ( root == NULL )

           return 0; // The tree is empty. It contains no nodes.

        else {

           int count = 1;   // Start by counting the root.

           count += countNodes(root->left); // Add the number of nodes

                                            //     in the left subtree.

           count += countNodes(root->right); // Add the number of nodes

                                            //    in the right subtree.

           return count; // Return the total.

        }

     } // end nodeCount()

In the programm I have used the preorder method to count the number of nodes in the binary tree...

I have executed it under codeblocks IDE.

#include <stdio.h>
#include <stdlib.h>
#include <iostream>
using namespace std;

/*
* Structure of node
*/
struct btnode
{
int value;
struct btnode *l;
struct btnode *r;
};
typedef struct btnode node;
node *ptr, *root = NULL;

void createbinary();
void preorder(node *);
int count(node*);
node* add(int);

int main()
{
int c;

createbinary();
preorder(root);
c = count(root);
cout << "\nNumber of nodes in binary tree are: " << c << endl;
return 0;
}
/*
* constructing the following binary tree
* 50
* / \
* 20 30
* / \
* 70 80
* / \ \
*10 40 60
*/
void createbinary()
{
root = add(50);
root->l = add(20);
root->r = add(30);
root->l->l = add(70);
root->l->r = add(80);
root->l->l->l = add(10);
root->l->l->r = add(40);
root->l->r->r = add(60);
}

/*
* Add the node to binary tree
*/
node* add(int val)
{
ptr = (node*)malloc(sizeof(node));
if (ptr == NULL)
{
cout << "Memory was not allocated" << endl;
exit(0);
}
ptr->value = val;
ptr->l = NULL;
ptr->r = NULL;
return ptr;
}

/*
* counting the number of nodes in a tree
*/
int count(node *n)
{
int c = 1;

if (n == NULL)
return 0;
else
{
c += count(n->l);
c += count(n->r);
return c;
}
}

/*
* Displaying the nodes of tree in preorder
*/
void preorder(node *t)
{
if (t != NULL)
{
printf("%d->", t->value);
preorder(t->l);
preorder(t->r);
}
}

CAUsers KanthlDesktop babulPlacement binary TreeTypelbinlDebuglbinary TreeType.exe 50-28-7e-18->48->80->60->30- Number of nodes in binary tree are: 8 Process returned (exe) execution time 0.031 s Press any key to continue