PROGRAM STACK AND QUEUE

public class node
{   node next;
    int data;
    node prev;
    public node(int data)
    {
        this.data=data;
        next=null;
    }
}



import java.util.Scanner;
public class jurnal1{
    int b,max;
    node head,tail;

    public jurnal1(){
    head=tail=null;
    b=0;}

    public void max(int x){
    max=x;}

    public void enqueue(int x){
        node baru =new node (x);
        if (head==null){
            head=baru;
            tail=baru;
            b=b+1;
        }
        else if(b<max){
            tail.next=baru;
            baru.prev=tail;
            tail=baru;
            b=b+1;}
        else {
            System.out.print("full");}
    }

    public void pop(){
        node temp=tail;
        tail=tail.prev;
        tail.next=null;
        temp=null;
        b=b-1;
    }

    public void dequeue(){
        node temp=head;
        head=head.next;
        temp=null;
        b=b-1;
    }
    public void tampil(){
        node temp=head;     if (head==null){
        System.out.print("kosong");}
        else{
            while (temp!=null){
            System.out.println("["+temp.data+"]");
            temp=temp.next;
            }
        }
    }
    public void tampil1(){
        node temp=tail;
        if (head==null){
        System.out.print("kosong");}
        else{
            while (temp!=null){
            System.out.println("["+temp.data+"]");
            temp=temp.prev;
            }
        }
    }



    public static void main(String[] args)
    {
        Scanner scan = new Scanner(System.in);
        jurnal1 ll = new jurnal1();
        int w=0;
        System.out.println("Linked jurnal1 Test\n");
        char ch;
        do
        {

        System.out.println("\nLinked jurnal1 Operations");
        System.out.println("1. maks");
        System.out.println("2. enqueue");
        System.out.println("3. dequeue");
        System.out.println("4. push");
        System.out.println("5. pop");
        System.out.println("6. tampil queue");
        System.out.println("7. tampil stack");
        int choice = scan.nextInt();
        switch (choice){
        case 1 :
        System.out.println("masukan maks=");
        w=scan.nextInt();
        ll.max(w);break;
        case 2 :
        System.out.println("masukan nilai=");
        ll.enqueue(scan.nextInt());
        break;
        case 3 :
        ll.dequeue();
        break;
        case 4 :
        ll.enqueue(scan.nextInt());;break;
        case 5 :
        ll.pop();break;
        case 6 :
        ll.tampil();break;
        case 7 :
        ll.tampil1();break;}
        System.out.println("\nDo you want to continue (Type y or n) \n");
        ch = scan.next().charAt(0);
        w++;
        } while (ch == 'Y'|| ch == 'y');

    }
}