import java.util.Stack;

public class stack_methods {
    public static void main(String[] args) {
      Stack<Integer> s = new Stack<>();
      s.push(1);
      s.push(2);
      s.push(3);
      pushAtBottom(4,s);

      reverse(s);
      while(!s.isEmpty()){
          System.out.println(s.peek());
          s.pop();
      }
    }
    public  static  void pushAtBottom(int data, Stack<Integer> s){
        if(s.isEmpty()){
            s.push(data);
            return;
        }
        int top = s.pop();
        pushAtBottom(data,s);
        s.push(top);
    }
    public static void reverse(Stack<Integer> s){
        if (s.isEmpty()){
            return;
        }
        int top = s.pop();
        reverse(s);
        pushAtBottom(top,s);
    }
}