BST code DSA

#include <iostream>
using namespace std;

struct node{
  int data;
  node *left;
  node *right;
};

class BST{
    public:
    node *root;
    node *t;
    BST(){
        t = NULL;
        root = NULL;
    }

    node* getroot(){
        return this->root;
    }

    void insert(int key){
        node* nn = new node;
        nn -> data = key;
        nn -> left = NULL;
        nn -> right = NULL;
        if(root == NULL){
            root = nn;
        }
        else{
            node* t = root;
            node* p = NULL;
            while(t != NULL){
                p = t;
                if(t -> data < nn -> data){
                    t = t -> right;
                }
                else if(t -> data > nn -> data){
                    t = t -> left;
                }
            }
            if(p -> data < nn -> data){
                p -> right = nn;
            }
            else{
                p -> left = nn;
            }
        }
    }

    void inorder(struct node* temp){
        if (!temp)
            return;
        inorder(temp -> left);
        cout << temp -> data << " ";
        inorder(temp -> right);
    }

    void preorder(struct node* temp){
            if (!temp)
                return;
            cout << temp -> data << " ";
            preorder(temp -> left);
            preorder(temp -> right);
    }

    void postorder(struct node* temp){
            if (!temp){
                return;
            }
            postorder(temp -> left);
            postorder(temp -> right);
            cout << temp -> data << " ";
    }

    void del(int key){
        node* p = NULL;
        node* t = root;

        while(t!=NULL && t->data != key){
            p = t;
            if(key<t->data)
                t = t->left;
            else if(key> t->data)
                t = t->right;
        }
        if(t==NULL){
            cout<<"Data Not found"<<endl;
            return;
        }

        if(t->left == NULL && t->right == NULL ){
            if(p!=NULL){
                if(p->left == t)
                    p->left = NULL;
                else if(p->right == t)
                    p->right = NULL;
            }
            else{
                root = NULL;
            }
        }
        else if(t->left == NULL && t->right != NULL ){
            if(p!=NULL){
                    if(p->left == t)
                        p->left = t->right;
                    else if(p->right == t)
                        p->right = t->right;
            }
            else{
                root = t->right;
            }
        }
        else if(t->left != NULL && t->right == NULL ){
            if(p!=NULL){
                if(p->left == t)
                    p->left = t->left;
                else if(p->right == t)
                    p->right = t->left;
            }
            else{
                root = t->left;
            }
        }
        else if(t->left != NULL && t->right != NULL ){
            node* inSuc = t->right;
            while(inSuc->left !=NULL)
                inSuc = inSuc->left;
            int val = inSuc->data;
            del(inSuc->data);

            t->data = val;
        }
    }
    /* void del(int key){
        node *parent = NULL;
        node *t = root;
        while(t != NULL && t -> data != key){
            if(key < t -> data){
                parent = t;
                t = t -> left;
            }
            else if(key > t -> data){
                t = t -> right;
            }
        }
        if(t == NULL){
            cout << "Data not there" << endl;
        }

        else if(t -> left == NULL && t -> right == NULL){
            if(parent != NULL){
                if(parent -> left == t){
                    parent -> left = NULL;
                }
                else if(parent -> right == t){
                    parent -> right = NULL;
                }
            }
        }

        else if(t -> left == NULL && t -> right != NULL ){
                if(parent != NULL){
                        if(parent -> left == t)
                            parent -> left = t -> right;
                        else if(parent -> right == t)
                            parent -> right = t -> right;
                }
                else{
                    root = t -> right;
                }
        }

        else if(t -> left != NULL && t -> right == NULL ){
                if(parent != NULL){
                    if(parent -> left == t)
                        parent -> left = t -> left;
                    else if(parent -> right == t)
                        parent -> right = t -> left;
                }
                else{
                    root = t -> left;
                }
        }

        else if(t -> left != NULL && t -> right != NULL ){
                node* suc = t -> right;
                while(suc -> left != NULL)
                    suc = suc -> left;
                int val = suc -> data;
                del(suc -> data);
                t -> data = val;
            }
    }
    */

    /*void del(int key){
        node* nn=new node;
        nn->left=nn->right=NULL;
        node* p=NULL;
        node* t=root;
        while(t!=NULL && t->data!=key){
            p=t;
            if(key>t->data){
                t=t->right;
            }
            else if(key<t->data){
                t=t->right;
            }
        }
        if(t==NULL){
            cout<<"data not found\n";
        }
        else{
            if(key<p->data){
             p->left=nn;
        }
            else if(key>p->data){
                p->right=nn;
            }
        }
        free(t);
    }
    */

};

int main(){
    BST b;
    int ch = 10;
        while(ch != 0){
            cout << "\nEnter your choices: " << endl;
            cout << "1: Add data" << endl;
            cout << "2: Display inorder" << endl;
            cout << "3: Display preorder" << endl;
            cout << "4: Display postorder" << endl;
            cout << "5: Delete data" << endl;
            cout << "0: Exit" << endl;
            cin >> ch;
            switch(ch){
                case 1:
                    int key;
                    cout << "Enter the key" << endl;
                    cin >> key;
                    b.insert(key);
                    break;
                case 2:
                    b.inorder(b.getroot());
                    break;
                case 3:
                    b.preorder(b.getroot());
                    break;
                case 4:
                    b.postorder(b.getroot());
                    break;
                case 5:
                    cout << "Enter data to delete" << endl;
                    int k;
                    cin >> k;
                    b.del(k);
                    break;
            }
    }
    return 0;
}