public static void main(String[] args)
{
    Scanner in = new Scanner(System.in);

    Stack<Integer> value = new Stack<>();

    System.out.println("Enter one number or operator per line, E to quit. ");
    System.out.println("Current Value: " + value);

    boolean flag = false;

    while (!flag)
    {

        String input = in.nextLine();
        //  command is an operator, pop the arguments and push the result
        if (input.equals("+"))
        {


            value.push(value.pop() + value.pop());
        }
        else if (input.equals("-"))
        {
           Integer argument2 = value.pop();
           Integer argument3 = value.pop();

            value.push(argument3 - argument2);
        }
        else if (input.equals("*"))
        {
            value.push(value.pop() * value.pop());
        }
        else if (input.equals("/"))
        {
            Integer argument2 = value.pop();
            value.push(value.pop() / argument2);
        }
        else if (input.equals("E") || input.equals("e"))
        {
            flag = true;
        }
        else
        {
            // Is not operator push to stack
            value.push(Integer.parseInt(input));
        }
        System.out.println("Current value: "+value);
    }
}