在不使用克隆的情況下復(fù)制堆棧和隊(duì)列。例如，當(dāng)我調(diào)用一個(gè)傳遞堆棧的方法時(shí)，我不能修改保留傳遞的原始堆棧。我需要復(fù)制/克隆傳遞的 Stack 以在方法中更改/使用。我只能使用 Stack.java（附件）。我創(chuàng)建了以下輔助方法：public static Stack<CalendarDate> qToS(Queue<CalendarDate> q) {    Stack<CalendarDate> s = new Stack<CalendarDate>();    while (!q.isEmpty()) {       CalendarDate n = q.remove();       s.push(n);    }    return s; // Return stack s}public static Queue<CalendarDate> sToQ(Stack<CalendarDate> s) {    Queue<CalendarDate> q = new LinkedList<CalendarDate>();    while (!s.empty()) {       CalendarDate n = s.pop();       q.add(n);    }    return q; // Return queue q}/*          Provided as a Stack Class alternative    Limits user to actual Stack methods    so Vector<E> is not available*/public class Stack<E> {    // avoid blanked import of java.util    private java.util.Stack<E> secret;    // default constructor    public Stack() {        secret = new java.util.Stack<E>();    }     // empty that collection    public void clear() {        secret.clear();    }    // should be order constant    public int size() {        return secret.size();    }    // simply have push call push from API    public E push(E a) {        secret.push(a);        return a;    }    // And, empty calls empty from API    public boolean empty() {        return secret.empty();    }    // And my pop() uses pop() form JAVA API    public E pop() {        return secret.pop();    }    // My peek uses their peek    public E peek() {        return secret.peek();    }    // Following are not basic Stack operations    // but needed to do some simple testing    // toString is probably not O(constant)    public String toString() {        return secret.toString();    }}