C Program to demonstrate Binary Tree through Array

#include<stdio.h>
#include<conio.h>
#include<graphics.h>
#include<dos.h>
#include<process.h>
#define MAX 10
// #define LEFTCHILD(K) 2K-1
// #define RIGHTCHILD(K) 2K
struct btree
{
   int data;
   int k;
}tree[100];
void initialize(struct btree tree[],int maxlength)
{
    int i;
    for(i=0;i<=maxlength;i++)
    {
       tree[i].data=-1;
       tree[i].k=0;
    }
}
void create(struct btree tree[],int num)
{
  int i;
  if(tree[0].data==-1)
  {
     tree[0].data=num;
     tree[0].k=1;
  }
  else
  {
     i=tree[0].k;
     while(tree[i-1].data!=-1 && i<=MAX)
     {
 if(tree[i-1].data>num)
 {
    i=2*tree[i-1].k;
 }
 else
 {
    i=2*tree[i-1].k+1;
 }
     }
     tree[i-1].k=i;
     tree[i-1].data=num;
  }
}
void display(void)
{
   int row=0,col=0,root=0;
   int i=0;
   for(i=0;i<=MAX;i++)
   {
     printf("\n %d",tree[i].data);
   }
   //getch();
}
void main()
{
  int length=10;
  char ch='y';
  int choice=0;
  int key=0;
  clrscr();
  do
  {
     clrscr();
     printf("\n\t <<< ARRAY REPRESENTATION OF BINARY TREE >>>\n");
     printf("\n 1. Initialize. ");
     printf("\n 2. Insert. ");
     printf("\n 3. Delete. ");
     printf("\n 4. Display. ");
     printf("\n 5. EXIT. \n");
     printf("\n Enter Your Choice : ");
     scanf("%d",&choice);
     switch(choice)
     {
 case 1:
     // INITIALIZE
     initialize(tree,length);
     printf("\n Binary Tree Initialized. \n");
     break;
 case 2:
     // INSERT
     printf("\n Enter The Key : ");
     scanf("%d",&key);
     create(tree,key);
     break;
 case 3:
     // DELETE
     break;
 case 4:
    // DISPLAY
    display();
    break;
 case 5:
    // EXIT
    exit(1);
 default:
    printf("\n Invalid Choice . Try Again...");
      }
      fflush(stdin);
      printf("\n Do you Wish to continue [y/n] :");
      ch=getch();
     }
     while(ch=='y');
     getch();
}