如何从上到下显示每个栈的内容？

Question

我想在下面的代码执行后输出每个堆栈的内容。到目前为止其输出为

Stack@568db2f2
Stack@378bf509
Stack@378bf509

但我想要每个堆栈的内容。

public static void main(String[] args) {
    Stack<Integer> a = new Stack<>();
    Stack<Integer> b = new Stack<>();
    Stack<Integer> c = new Stack<>();

    a.push(28);
    b.push(a.pop());
    b.peek();
    c.push(21);
    a.push(14);
    a.peek();
    b.push(c.pop());
    c.push(7);
    b.push(a.pop());
    b.push(c.pop());

    System.out.println(a);
    System.out.println(b);
    System.out.println(b);

}

Answer 1

类stack的默认toString()打印堆栈在内存中的位置或类似的内容，而不是打印堆栈的内容。您应该对每个堆栈使用以下代码（stk是您要打印其内容的原始堆栈taht）：

//Create another temporary Stack
Stack<Integer> temp = new Stack<>();

//Print each content of the original Stack (stk) separately.
//Move each content to the temporary Stack (temp), in order to preserve it.
while(! stk.empty())
   {
       System.out.println(stk.peek());
       temp.push(stk.pop());
   }

//Move all the content back to the original Stack (stk)
while(! temp.empty())
   {
       stk.push(temp.pop());
   }