Write a program to build a complete binary tree and to chek if it is a Binary Search Tree.

#include<stdio.h>

#include<stdlib.h>

int * createCompleteBinaryTree(int n);

void printCompleteBinaryTree(int * tree, int n);

int isBST(int * tree, int n);

int main()

{

          int n, * tree;

          printf("Enter the number of elements in the tree\n");

          scanf("%d",&n);

          tree = createCompleteBinaryTree(n);

          printCompleteBinaryTree(tree,n);

          if(isBST(tree,n))

                   printf("The tree is a BST\n");

          else

                   printf("The tree is not a BST\n");

          return 0;

}

int * createCompleteBinaryTree(int n)

{

          int i;

          int * tree = (int *) malloc((n)*sizeof(int));

          printf("Enter the elements in the tree\n");

          for(i=0;i<n;i++)

          {

                   scanf("%d",(tree+i));

          }

          return tree;

}

void printCompleteBinaryTree(int * tree, int n)

{

          int i;

          printf("The elements in the tree in level order are");

          for(i=0;i<n;i++)

                   printf(" %d",*(tree+i));

          printf("\n");

}

int isBST(int * tree, int n)

{

 int i,j=1,sum=0,m=0;

 m=n/2;

 for(i=0;i<m;i++)

 {

     sum=*(tree+i);

     if(sum<=*(tree+j))

     {

         if(j>=n)

         break;

         else

         return 0;

     }

     if(sum>=*(tree+j+1))

     {

         if((j+1)>=n)

         break;

         else

         return 0;

     }

    

     else{

     if(j>=n)

     break;

     j=j+2;

 }}

 return 1;

}