Implementation of binary search tree in C & C++

/* Binary Search Tree

   Roll no:- 09BCE006

*/

#include<iostream.h>

#include<stdio.h>

#include<conio.h>

#include<process.h>

struct tree

{

    int info;

    struct tree *lptr,*rptr;

}*root,*head,*hroot;

void insert(struct tree*,int);

void del(struct tree*,int);

void inorder(struct tree*);

void preorder(struct tree*);

void postorder(struct tree*);

void main()

{

    clrscr();

    int ch,x;

    char cho;

    while(1)

    {

       cout<<"\n\n1.INSERTION\n2.INORDER TRAVERSAL\n3.PREORDER TRAVERSAL\n";

       cout<<"4.POSTORDER TRAVERSAL\n5.DELETION\n6.EXIT\n";

       cout<<"Enter ur choice\n";

       cin>>ch;

       clrscr();

       switch(ch)

       {

        case 1:cout<<"Enter ur value whiich is to be inserted\n";

               cin>>x;

               insert(hroot,x);

            break;

        case 2:inorder(hroot);

               break;

        case 3:preorder(hroot);

               break;

        case 4:postorder(hroot);

               break;

        case 5:cout<<"enter the value";

               cin>>x;

               del(hroot,x);

               break;

        case 6:exit(1);

          }

    }

    getch();

}

void insert(tree *root,int x)

{

    tree *temp;

    temp=new tree;

    temp->info=x;

    temp->lptr=NULL;

    temp->rptr=NULL;

    if(root==NULL)

    {    hroot=root=temp;

    }

    else

    {if(root->info<temp->info)

    {

        if(root->rptr==NULL)

        {

            root->rptr=temp;

        }

        else

        {

            root=root->rptr;

            insert(root,x);

        }

    }

    else

    {

        if(root->lptr==NULL)

        {

            root->lptr=temp;

        }

        else

        {

            root=root->lptr;

            insert(root,x);

        }

    }

    }

}

void inorder(tree *root)

{

    if(root==NULL)

    {

        cout<<"\n TREE IS EMPTY\n";

        exit(0);

    }

    if(root->lptr!=NULL)

    {

        inorder(root->lptr);

    }

    cout<<endl<<root->info;

    if(root->rptr!=NULL)

    {

        inorder(root->rptr);

    }

    return;

}

void preorder(tree *root)

{

    if(root==NULL)

    {

        cout<<"\n TREE IS EMPTY\n";

        exit(0);

    }

    else

    {

        cout<<endl<<root->info;

    }

    if(root->lptr!=NULL)

    {

        preorder(root->lptr);

    }

    if(root->rptr!=NULL)

    {

        preorder(root->rptr);

    }

    return;

}

void postorder(tree *root)

{

    if(root==NULL)

    {

        cout<<"\n TREE IS EMPTY\n";

        exit(0);

    }

    if(root->lptr!=NULL)

    {

        postorder(root->lptr);

    }

    if(root->rptr!=NULL)

    {

           postorder(root->rptr);

    }

    cout<<endl<<root->info;

    return;

}

void del(tree *root,int n)

{

   tree *par,*p,*temp;

  if(root==NULL)

  {

   cout<<"tree is empty ";

   exit(0);

   }

   else

   {

    par=NULL;

    p=root;

    }

while(p!=NULL)

{

  if(n==p->info)

   {

     break;

    }

    else if(n<p->info)

       {

       par=p;

       p=p->lptr;

       }

       else

       {

       par=p;

       p=p->rptr;

       }

 }

  /* if(p->lptr!=NULL && p->rptr!=NULL)

     {

      par=p;

      }*/

   if(p->lptr==NULL && p->rptr==NULL)

      {

    temp=NULL;

      }

  else if(p->lptr!=NULL && p->rptr==NULL)

      {

       temp=p->lptr;

      }

  else if(p->lptr==NULL && p->rptr!=NULL)

       {

    temp=p->rptr;

       }

  if(par!=NULL)

   {

     if(p==par->lptr)

      {

    par->lptr=temp;

       }

      else

       {

     par->rptr=temp;

    }

    }

  else

  {

    p=temp;

   }

}