Reverse the order of a stack without new a container

import java.util.Stack; public class Test { public static void main(String[] args) { Stack<Integer> integers = new Stack<>(); integers.push(1); integers.push(2); integers.push(3); integers.push(4); reverse(integers); System.out.println("integers = " + integers); } private static int f(Stack<Integer> stack){ int result = stack.pop(); if(stack.isEmpty()){ return result; }else{ int last = f(stack); stack.push(result); return last; } } private static void reverse(Stack<Integer> stack){ if(stack.isEmpty()){ return; } int i = f(stack); reverse(stack); stack.push(i); }}Copy the code