Using one stack to sort another stack

subject ：

      

 The type in a stack is integer , Now I want to sort the stack from top to bottom in order from small to large , Only one stack is allowed 
 besides , You can apply for new variables , But you can't apply for additional data structures , How to sort .

Ideas ：

       To design a cur Variable , Deposit stack The current element popped from the stack , And auxiliary stack help Compare the top elements of the stack , If it is larger than the top element of the auxiliary stack , Then pop up the elements in the auxiliary stack one by one , Push the stack In the stack , If it is smaller than the top element of the auxiliary stack , Will cur Push into auxiliary stack , know stack The stack is empty. , Then pop up and press the auxiliary stack one by one stack In the stack , Sort complete .

public class test1 {
    public void sortStack() {
        Stack<Integer> help = new Stack<>();
        Stack<Integer> stack = new Stack<>();
        while (!stack.isEmpty()) {
            int cur = stack.pop();
            while (!help.isEmpty() && cur > help.peek()) {
                stack.push(help.pop());
            }
            help.push(cur);
            while (!help.isEmpty()){
                stack.push(help.pop());
            }
        }
    }
}