Stack and Queue

#include <iostream>

using namespace std;

class node{
    public:
    int data;
    node* Next;
    node(int num = 0){
        data = num;
        Next = nullptr;
    }
};


class Stack{
    public:
    node* top;
    int size;
    Stack(){
        top = nullptr;
        size = 0;
    }

    void push(int num){
        node* newnode = new node(num);
        newnode ->Next = top;
        top = newnode;
        size++;
    }

    int printSt(){
        if(top == nullptr) return -1;
        else return top->data;
    }

    void pop(){
        if(top){
        node* deletenode = top;
        top = top->Next;
        delete deletenode;
        size--;}
    }

    int Size(){
        return size;
    }

    bool is_empty(){
        return (top == nullptr);
    }


    ~Stack(){
        while(top){
            node* newnode = top;
            top = top -> Next;
            delete newnode;
        }
    }

};


class Queue{
    public:
    node* front;
    node* back;
    int size;

    Queue(){
        front = nullptr;
        back = front;
        size = 0;
    }

    int Size(){
        return size;
    }

    void push(int num){
       if(!front){
        back = front = new node(num);
        }else{
            back->Next = new node(num);
            back = back->Next;
        }
        size++;

    }

    int Front(){
        if(front){
            return front->data;
        }
        return -1;
    }

    int Back(){
        if(back){
            return back->data;
        }
        return -1;
    }

    void Pop(){
        if(front){
            node* deletenode = front;
            front = front->Next;
            delete deletenode;
            size--;
        }
    }

    bool is_empty(){
        return (front == nullptr);
    }

    ~Queue(){
        while(front){
            node* newnode = front;
            front = front -> Next;
            delete newnode;
        }
    }

};




int main(){
    Stack st;
    st.push(9);
    st.push(10);
    st.push(8);
    cout << st.printSt() << endl;
    st.pop();
    cout << st.printSt() << endl;
    st.pop();
    st.pop();
    cout << "size : " << st.Size() << endl;
    cout << st.printSt() << endl;


    /////////////////////////////////////////////////////
    Queue q;
    cout << q.is_empty() << endl;
    q.push(10);
    q.push(8);
    q.push(11);
    q.push(13);
    cout << q.Front() << " " << q.Back() << endl;
    q.Pop();
    cout << q.Front() << " " << q.Back() << endl;
    cout << q.is_empty() << " " << q.Size();


}