task 1( ds lab 7) 3rd sem

#include<bits/stdc++.h>
using namespace std;
int y;
struct node
{
    int data;
    struct node* left;
    struct node* right;
};
typedef struct node Node;
Node* create_node(int item)
{
    Node* new_node=new Node();
    if(new_node==NULL)
        cout<<"Error"<<endl;
    else
    {
        new_node->data=item;
        new_node->left=new_node->right=NULL;
    }
    return new_node;
}
void inorder(Node* x)
{
    if(x!=NULL)
    {
        inorder(x->left);
        cout<<x->data<<" ";
        inorder(x->right);
    }
}
Node* insert_key(Node* x,int key)
{
    Node* new_node=create_node(key);
    if(x==NULL)
        return new_node;
    if(key>x->data+3)
    {
        x->right=insert_key(x->right,key);
    }
    else if(key<x->data-3)
    {
        x->left=insert_key(x->left,key);
    }
    else
        y=0;
    return x;
}
int main()
{
    Node* root=NULL;
    while(1)
    {
        int n;
        cin>>n;
        y=1;
        if(n!=-1)
        {
            root=insert_key(root,n);
            inorder(root);
            if(y==0)
            cout<<"(Reservation failed)"<<endl;
            else
                cout<<endl;
        }
        else
            break;
    }
}