BST_Searching.cpp

#include<iostream>
#include<queue>

using namespace std;

class node
{
public:
    node* left;
    node* right;

    int data;

    node(int d)
    {
        data=d;
        right=left=NULL;
    }
};
//Accepts the old root node & data and returns the new node
node* InsertInBST(node *root,int data)
{
    //Base case
    if(root==NULL)
    {
        return new node(data);
    }
    //Rec case - Insert in the subtree and update pointers

    if(data<=root->data)
    {
        root->left=InsertInBST(root->left,data);
    }
    else
    {
        root->right=InsertInBST(root->right,data);
    }

    return root;
}
node* build()
{
    //read a list of numbers till -1 and also these numbers will be inserted into BST
    int d;
    cin>>d;

    node*root=NULL;
    while(d!=-1)
    {
        root=InsertInBST(root,d);
        cin>>d;
    }

    return root;
}

void Inorder(node *root)
{
    if(root==NULL)
    {
        return;
    }

    Inorder(root->left);
    cout<<root->data<<", ";
    Inorder(root->right);

}
bool search(node *root,int data)
{
    if(root==NULL)
    {
        return false;
    }
    if(root->data==data)
    {
        return true;
    }
    //recursive case call on left or right subtree

    if(data<=root->data)
    {
        return search(root->left,data);
    }
    else
    {
        return search(root->right,data);
    }
}
int main()
{
    node* root=build();

    Inorder(root);
    cout<<endl;

    int s;
    cin>>s;

    if(search(root,s))
    {
        cout<<"Present"<<endl;
    }
    else
    {
        cout<<"not present"<<endl;
    }


    return 0;
}