在toString方法中返回动态堆栈链接列表的所有值

public class Stack {
    private Node top;

    private class Node {
        private Object value;
        private Node next;

        public Node(Object value) {
            this.value = value;
        }
    }

    public void push(Object value) {
        Node newNode = new Node(value);
        if (top == null) {
            top = newNode;
        } else {
            newNode.next = top;
            top = newNode;
        }
    }

    public Object pop() {
        if (top == null) {
            throw new NoSuchElementException("Stack is empty");
        }
        Object value = top.value;
        top = top.next;
        return value;
    }

    public String toString() {
        StringBuilder sb = new StringBuilder();
        Node current = top;
        while (current != null) {
            sb.append(current.value).append(" ");
            current = current.next;
        }
        return sb.toString();
    }
}