DS (II) Assignment 2: Set A- a)

a) Write a C program which uses Binary search tree library and displays nodes at each level, count of node at each level and total levels in the tree.

Solution: 

#include<stdio.h>
#include<stdlib.h>
#include "btree.h"
struct Qnode
{
struct TreeNode *node;
struct Qnode *next;
}*front, *rear;
void initQ()
{
front=rear=NULL;
}
int isQEmpty()
{
    if(front==rear && rear==NULL)
{
        printf("\nQueue Empty\n");
        return 1;
    }
    return 0;
}
void enqueue(struct TreeNode *Tnode)
{
    struct Qnode *nptr = (struct Qnode*)malloc(sizeof(struct Qnode));
    nptr->node = Tnode;
    nptr->next = NULL;
    if (rear == NULL)
    {
    front = nptr;
    rear = nptr;
    }
    else
    {
    rear->next = nptr;
    rear = rear->next;
    }
}
struct Qnode * dequeue()
{
    struct Qnode *temp;
    if (front == NULL)
    {
        printf("\n\nQueue is empty \n");
    }
    else
    {
        temp = front;
        front = front->next;
        if(temp == rear)
{
        rear = front;
    }
    }
    return temp;
}
void levelOrderTraversal(struct TreeNode * root) 
{
    struct TreeNode *curr,*ptr;
    int total,cnt,level;
    struct Qnode *temp;
    total=cnt=level=0;
    enqueue(root);
    ptr=(struct TreeNode*)malloc(sizeof(struct TreeNode));
    ptr->data=0;
    ptr->left=ptr->right=NULL;
    enqueue(ptr);
    //enqueue(NULL);
    while(front!=rear)
    {
     temp=dequeue();
if(temp->node->data!=0)
{
            total++;
    cnt++;
    printf("%d\t",temp->node->data);
    if(temp->node->left)
        enqueue(temp->node->left);
    if(temp->node->right)
enqueue(temp->node->right);
}
else
{
    printf("\nNo of node in level %d = %d\n",level, cnt);
    cnt=0;
    level++;
    ptr=(struct TreeNode*)malloc(sizeof(struct TreeNode));
        ptr->data=0;
        ptr->left=ptr->right=NULL;
        enqueue(ptr);

        }
    }
    printf("\nNo of node in level %d = %d\n",level, cnt);
    cnt=0;
    level++;
    printf("\nTotal Nodes= %d\nNumber of Levels = %d\n",total,level-1);
}
int main()
{
    int val;
    struct TreeNode *root;
    root=NULL;
    initQ();
    printf("\n#-#-#-\t\tBST Construction\t-#-#-#\n");
    while(1)
    {
        printf("\nEnter The Tree Node Data:\t");
        scanf("%d", &val);
        if(val==0)
        break;
        else
        {
        root=insert(root, val);
        }
    }
    printf("\n\n\tLevel Order Traversal\n");
    levelOrderTraversal(root);
    return 0;
}

Library Function ( .h file )
NOTE: save file name as ' btree.h'. 

#include<stdio.h>
#include<stdlib.h>
struct TreeNode
{
    struct TreeNode *left;
    int data;
    struct TreeNode *right;
};
struct TreeNode *insert(struct TreeNode *root, int x)
{
    if(root==NULL)
    {
        root=(struct TreeNode*)malloc(sizeof(struct TreeNode));
        root->data=x;
        root->left=root->right=NULL;
        return(root);
    }
    else if(x<root->data)
    {
        root->left=insert(root->left, x);           
    }
    else if(x>root->data)
        root->right=insert(root->right, x);
    return(root);
}
void inorder(struct TreeNode *root)
{
    if(root!=NULL)
    {
        inorder(root->left);
        printf(" %d ", root->data);
        inorder(root->right);
    }
}