Friday, 30 September 2016

Binary Search Tree Creation and Traversals

Binary Search Tree Creation and Level-order, Inorder, Preorder, Postorder Traversals


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

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);
            }
}

void inorder(NODE root)
{
            if(root != NULL)
            {
                        inorder(root->lchild);
                        printf("%d ", root->data);
                        inorder(root->rchild);
            }
}

void preorder(NODE root)
{
            if (root != NULL)
            {
                        printf("%d ", root->data);
                        preorder(root->lchild);
                        preorder(root->rchild);
            }
}

void postorder(NODE root)
{
            if (root != NULL)
            {
                        postorder(root->lchild);
                        postorder(root->rchild);
                        printf("%d ", root->data);
            }
}

void levelorder(NODE root)
{
            NODE q[40],cur;
            int front=0,rear=-1;
            q[++rear]=root;
            while(front<=rear)
            {
                        cur = q[front++];
                        printf("%d ",cur->data);
                        if(cur->lchild != NULL)
                                    q[++rear] = cur->lchild;
                        if(cur->rchild != NULL)
                                    q[++rear] = cur->rchild;
            }
}
void main()
{
            int val, i,n;
            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);
            }
            if (root == NULL)
                        printf("\nTree Is Not Created");
            else
            {
                        printf("\nThe Levelorder display : ");
                        levelorder(root);
                        printf("\nThe Inorder display : ");
                        inorder(root);
                        printf("\nThe Preorder display : ");
                        preorder(root);
                        printf("\nThe Postorder display : ");
                        postorder(root);
            }
}


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

The Levelorder display :        6          5          9          2          8          15        7          14        24
The Inorder display :             2          5          6          7          8          9          14        15        24
The Preorder display :           6          5          2          9          8          7          15        14        24
The Postorder display :         2          5          7          8          14        24        15        9          6

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