IoT C++ 09/23 - Binary Search Tree Example (Interger/InCPT)

#include<iostream>
#include<cstdlib>
#define NULL __null

using namespace std;

typedef struct treenode {
    int data;
    struct treenode* left;
    struct treenode* right;
} treenode;

treenode* input(treenode* node, int data)
{
    if(node == NULL){
        treenode* num;
        //cout<<"[node]"<<endl;
        num = new treenode[100];
        num->data = data;
        num->left = NULL;
        num->right = NULL;
        return num;
    }
    else if (data < node->data){
        //cout<<"[left]"<<endl;
        node->left = input(node->left,data);
    }
    else if(data > node->data){
        //cout<<"[right]"<<endl;
        node->right = input(node->right,data);
    }
    else{
        cout<<"ERROR>Already R0egistered"<<endl;
        return node;
    }
}

void preorder(treenode* node)
{
    cout<<node->data<<" ";
    if (node->left) preorder(node->left);
    if (node->right)    preorder(node->right);
}

void ctrorder(treenode* node)
{
    if (node->left) ctrorder(node->left);
    cout<<node->data<<" ";
    if (node->right)    ctrorder(node->right);
}

void lstorder(treenode* node)
{
    if (node->left) lstorder(node->left);
    if (node->right)    lstorder(node->right);
    cout<<node->data<<" ";
}

void search(treenode* node , int data)
{
    if(node == NULL){
        cout<<"ERROR>NONE TREENODE!"<<endl;
        return;
    }
    else if(data == node->data) {
        cout<<"CENTRE NUM>"<<node->data<<endl;
        if(node->left!=NULL)cout<<"LEFT NUM>"<<node->left->data<<endl;
        else cout<<"LEFT NUM>"<<"None"<<endl;
        if(node->right!=NULL)cout<<"RIGHT NUM>"<<node->right->data<<endl;
        else cout<<"RIGHT NUM>"<<"None"<<endl;
        return;
    }
    else if (data < node->data) {
        search(node->left,data);
    }
    else if (data > node->data) {
        search(node->right,data);
    }
    else {
     cout<<"ERROR>SEARCH ERROR!"<<endl;
    }
}
void delnum(treenode* node , int data)
{
    if(data == node->data) {
        if(data==5){
            cout<<"ERROR>NO! DEL 1STCTR NUMBER"<<endl;
        }
        else{
            node->data = (int)NULL;
            if(node->left!=NULL) node->left = NULL;
            if(node->right!=NULL) node->right = NULL;
        }
    }
    else if (data < node->data) {
        delnum(node->left,data);
    }
    else if (data > node->data) {
        delnum(node->right,data);
    }
    else {
     cout<<"ERROR>DELETE ERROR!"<<endl;
    }
}


int main(void)
{
    int num, select;
    treenode* node;
    node=NULL;
    cout<<"1STCTR>"; cin>>num;
    node = input(node,num);
    while(1)
    {
        cout<<"Input(OUT:-1)>"; cin>>num;
        if(num==-1)
            break;
        input(node,num);
    }
    while(2)
    {
        cout<<"Menu> 1)ALLVIEW , 2)SELECT_VIEW, 3)DELETE 4)EXIT"<<endl;
        cout<<"Select>"; cin>>select;
        if(select==4) break;
        switch(select)
        {
            case 1:
            {
                cout<<"pre>"; preorder(node); cout<<endl;
                cout<<"ctr>"; ctrorder(node); cout<<endl;
                cout<<"lst>"; lstorder(node); cout<<endl;
                break;
            }
            case 2:
                cout<<"Msg>ENTER U WANT VIEW NUMBER"<<endl;
                cout<<"Input>"; cin>>select;
                search(node , select);
                break;
            case 3:
                cout<<"Msg>ENTER U WANT DEL NUMBER"<<endl;
                cout<<"Input>"; cin>>select;
                delnum(node , select);
                break;
            default:
                cout<<"Invalid Select"<<endl; break;
        }
        cout<<endl;
    }
    delete[] node; node=NULL;
    cout<<"ByeBye"<<endl;
    return 0;
}