I will do the addition multiplication and print operations of two separate polynomials that I will get from the user. However, when creating two linkedlists in the main class, the nodes that I added to the first linkedlist are replaced by the nodes that I added to the second linkedlist. How can I solve this?

public class Main {
    public static void main(String[] args) {
        Scanner scn = new Scanner(System.in);
        int coefficient, degree;
        int coef, deg;
        MyLinkedList ml, ml2;

        ml = new MyLinkedList();
        System.out.println("Enter the coefficient and power of the first polynomial. Type 0 at the end: ");
        coefficient = scn.nextInt();
        degree = scn.nextInt();
        ml.insertLast(coefficient, degree);
        //System.out.println(ml.toString());

        while (true) {
            if (coefficient != 0) {
                coefficient = scn.nextInt();
                degree = scn.nextInt();
                ml.insertLast(coefficient, degree);
            } else {
                break;
            }
        }
        //System.out.println(ml.toString());
        ml2 = new MyLinkedList();
        System.out.println("Enter the coefficient and power of the second polynomial. Type 0 at the end: ");
        coef = scn.nextInt();
        deg = scn.nextInt();
        ml2.insertLast(coef, deg);
        //System.out.println(ml2.toString());
        while (true) {
            if (coef != 0) {
                coef = scn.nextInt();
                deg = scn.nextInt();
                ml2.insertLast(coef, deg);
            } else {
                break;
            }
        }
    }
}
public class MyLinkedList {
    static Node first;
    static Node last;
    static int size = 0;
    public MyLinkedList() {
        first = null;
        last = null;
        size = 0;
    }
    public static void insertLast(int x,int y) {
        Node newNode = new Node(x,y);
        if (first == null) {
            first = newNode;
            last = newNode;
        } else {
            last.next = newNode;
            last = newNode;
        }
        size  ;
    }

    public String toString() {
        Node tmp = first;
        String str = "";

        while (tmp != null) {
            str  = tmp.coef   "x^"  tmp.power   "->";
            tmp = tmp.next;
        }
        return str;
    }
}

CodePudding user response：

Inside your LinkedList class you declare your Nodes "first" and "last" as static. This means that both LinkedLists share the same first and last. You wont be able to have a separate linked list if they remain static.