显示并添加随机生成的数字的总和（和平均值）（j

Question

我正在尝试计算“餐厅等候名单”申请的总“等待时间”和平均等待时间。我无法想出那部分，我试图显示总数，但它会一直显示总数。我正在使用链表，并希望它在添加人员到候补名单时继续添加。我也不知道如何显示平均值，因为名称是一个字符串，如果我做总数/名称，它会给我一个错误。如果我将它解析为Int，它会给我一个错误。任何帮助，将不胜感激。当我单击以下按钮时，它应显示运行总计。

private void btnAddActionPerformed(java.awt.event.ActionEvent evt) {                                       

        Random rand = new Random();

        String name = txtName.getText();

        int  time = rand.nextInt(30) + 1;

        int totaltime = time;


        int partySize = Integer.parseInt(txtSize.getText());



            txtTotal.setText(String.valueOf(totaltime) + " minutes until your table is ready.");
            Highest = partySize;


        String result = " Name: " + txtName.getText() + "      Party Size: " + partySize + "      Wait Time: " + time + " minutes.";

            stack.enqueue(result);
            Wait++;

    }                                      

    private void btnDisplayActionPerformed(java.awt.event.ActionEvent evt) {                                           
        String result;
        int s;
        int size = stack.size();
        lstOutput.removeAll();
        for (s = 0; s < size; s++) {
            result = (String)stack.dequeue();
            lstOutput.add(result);

        }
    } 

stack是我的LinkedList。     LinkedListStack stack = new LinkedListStack（）;

这是LinkedListStack

public class LinkedListStack<E> implements QueueInterface<E> {

    private LinkedList<E> list = new LinkedList<>(); // an empty list

    public LinkedListStack() {
    } // new queue relies on the initially empty list

    public int size() {
        return list.getSize();
    }

    public boolean isEmpty() {
        return list.isEmpty();
    }

    public void enqueue(E element) {
        list.addLast(element);
    }

    public E first() {
        return list.first();
    }

    public E dequeue() {
        return list.removeFirst();
    }
}

这是我的QueueInterface

public interface QueueInterface<E> {

    int size();

    boolean isEmpty();

    // adds an item to the stack
    void enqueue(E e);

    // return but not remove the top item on the stack
    E first();

    // remove item at the top of the stack
    E dequeue();  
}

这是我正在使用的LinkedList。

public class LinkedList<E> {
    private int size;
    private Node<E> head;
    private Node<E> tail;

    // default constructor
    public LinkedList() {
        size = 0;
        head = null;
        tail = null;
    }

    // read-only property
    public int getSize() {
        return size;
    }

    public boolean isEmpty() {
        // replaces an if/else
        return (size == 0);
    }

    // return but not remove head of the list
    public E first() {
        if ( isEmpty() ) {
            return null;
        }
        else {
            return head.getElement();
        }
    }

    public E last() {
        if ( isEmpty() ) {
            return null;
        }
        else {
            return tail.getElement();
        }
    }

    public void addFirst(E e) {
        // create a new node and make it the new head of the list
        head = new Node<>(e, head);

        if (size == 0) {
            tail = head; // special case first item in the list
        }

        size++;
    }

public void addLast(E e) {
    // create a new node and add to the tail of the list
    Node<E> newest = new Node<>(e, null);
    if (size == 0) {   // special case for the first item
        head = newest; // now head points to the new node
    }
    else {
        tail.setNext(newest);
    }

    tail = newest;
    size++;
}

    public E removeFirst() {
        if (isEmpty() ) {
            return null;
        }
        else {
            E tets = head.getElement();
            head = head.getNext();
            size--;
            if (size == 0) {
                tail = null; // list is now empty
            }
            return tets;
        }
    }


    // nested class
    public class Node<E> {
        private E element;
        private Node<E> next;

        // custom constructor
        public Node(E e, Node<E> n) {
            element = e;
            next = n;
        }

        // get element
        public E getElement() {
            return element;
        }

        public Node<E> getNext() {
            return next;
        }

        public void setNext(Node<E> n) {
            next = n;
        }
    } // end nested node class

} // end of LinkedList