C program to implement Binary tree

C program to implement Binary tree

#include<stdio.h>
#include<conio.h>
#include<alloc.h>

struct node
{
 int data;
 struct node *left,*right;
};
struct node *root;
  
void insert(int x)
{
 struct node *p,*previous,*current;
 p=(struct node *)malloc(sizeof(struct node));
 if(p==NULL)
 {
  printf("n Out of memory");
 }
 p->data=x;
 p->left=NULL;
 p->right=NULL;
 if(root=NULL)
 {
  root=p;
  return;
 }
 previous=NULL;
 current=root;
 while(current!=NULL)
 {
  previous=current;
  if(p->data<current->data)
   current=current->left;
  else
   current=current->right;
 }
 if(p->data<previous->data)
  previous->left=p;
 else
  previous->right=p;
}
 
void inorder(struct node *t)
{
 if (t!=NULL)
 {
  inorder(t->left);
  printf("n %5d",t->data);
  inorder (t->right);
 }
}
 
void del(int x)
{
 int tright=0,tleft=0;
 struct node *ptr=root;
 struct node *parent=root;
 struct node *t1=root;
 struct node *temp=root;
 while(ptr!=NULL&& ptr->data!=x)
 {
  parent=ptr;
  if (x<ptr->data)
  ptr=ptr->left;
   else
  ptr=ptr->right;
 }
 if (ptr==NULL)
 {
  printf("n Delete element not found");
  return ;
 }
 else if(t1->data==x && (t1->left ==NULL || t1->right==NULL))
  if(t1->left==NULL)
   t1=t1->right;
  else
   t1=t1->left;
 else if (ptr->left==NULL)
  if (x<parent->data)
   parent->left=ptr->right;
  else
   parent->right=ptr->right;
 else if (ptr->right==NULL)
  if (x<parent->data)
   parent->left=ptr->left;
  else
   parent->right=ptr->left;
 else
 {
  temp=ptr;
  parent=ptr;
  if((ptr->left)>=(ptr->right))
  {
   ptr=ptr->left;
   while(ptr->right!=NULL)
   {
    tright=1;
    parent=ptr;
    ptr=ptr->right;
   }
   temp->data=ptr->data;
   if(tright)
    parent->right=ptr->left;
   else
    parent->left=ptr->left;
  }
  else
  {
   ptr=ptr->right;
   while (ptr->left!=NULL)
   {
    tleft=1;
    parent=ptr;
    ptr=ptr->left;
   }
   temp->data=ptr->data;
   if(tleft)
    parent->left=ptr->right;
   else
    parent->right=ptr->right;
  }
  free(ptr);
 }
}

void main()
{
 int op,n,srchno;
 root=(struct node *)malloc(sizeof(struct node));
 root->data=30;
 root->right=root->left=NULL;
 clrscr();
 do
 {
  printf("n 1.Insertion");
  printf("n 2.Deletion");
  printf("n 3.Inorder");
  printf("n 4.Quit");
  printf("n Enter your choicen");
  scanf("%d",&op);
  switch (op)
  {
  case 1: printf("n Enter the element to insertn");
  scanf("%d",&n);
  insert(n);
  break;
  case 2: printf("n Enter the element to be deletedn"); scanf("%d",&srchno);
  del(srchno);
  break;
  case 3: printf("n The inorder elements aren"); inorder(root);
  getch();
  break;
  default: exit(0);
  }
 }while(op<4);
 getch();
}