Friday, 30 September 2016

Binary Search Tree: Count number of nodes

Count number of nodes in Binary Search Tree


#include<stdio.h>
#include<stdlib.h>
struct BST
{
            int data;
            struct BST *lchild;
            struct BST *rchild;
};
typedef struct BST * NODE;
int count = 0;

NODE get_node()
{
            NODE temp;
            temp = (NODE) malloc(sizeof(struct BST));
            temp->lchild = NULL;
            temp->rchild = NULL;
            return temp;
}

void insert(NODE root, NODE newnode)
{
            if (newnode->data < root->data)
            {
                        if (root->lchild == NULL)
                                    root->lchild = newnode;
                        else
                                    insert(root->lchild, newnode);
            }
            if (newnode->data > root->data)
            {
                        if (root->rchild == NULL)
                                    root->rchild = newnode;
                        else
                                    insert(root->rchild, newnode);
            }
}

int count_nodes(NODE root)
{
            if(root == NULL)
                        return 0;
            count++;
            count_nodes(root->lchild);
            count_nodes(root->rchild);
            return count;
}

void main()
{
            int val, i,n, cn, ln;
            NODE root = NULL, newnode;
            printf("\nEnter the number of elements: ");
            scanf("%d",&n);
            for(i=1;i<=n;i++)
            {
                        newnode = get_node();
                        printf("\nEnter The node value: ");
                        scanf("%d", &val);
                        newnode->data = val;
                        if (root == NULL)
                                    root = newnode;
                        else
                                    insert(root, newnode);
            }
            cn = count_nodes(root);
            printf("\nTotal number of nodes in the tree is: %d", cn);
}

Output:
Enter the number of elements: 12
Enter The node value: 6
Enter The node value: 9
Enter The node value: 5
Enter The node value: 2
Enter The node value: 8
Enter The node value: 15
Enter The node value: 24
Enter The node value: 14
Enter The node value: 7
Enter The node value: 8
Enter The node value: 5
Enter The node value: 2
 Total number of nodes in the tree is: 9

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