using System;

​

public class Program

{

    public static float scratchpad, od, oc;

    public static int odocmode = 0;

    public static bool decimalmode = false;

    public static void Main()

    {

        KeyPad("1");

        KeyPad("2");

        KeyPad("9");

        KeyPad("9");

        KeyPad("9");

        KeyPad("D");

        KeyPad("ENTER");

        KeyPad("2");

        KeyPad("2");

        KeyPad("C");

        KeyPad("ENTER");

        KeyPad("1");

        KeyPad("2");

        KeyPad(".");

        KeyPad("2");

        KeyPad("ENTER");

    }

​

    public static void KeyPad(string input)

    {

        int j;

        if (scratchpad < 999.9f)

        {

            if (decimalmode == false)

            {

                if (int.TryParse(input, out j))

                {

                    scratchpad = (scratchpad * 10) + j;

                }

            }

            if (decimalmode == true){

                if (int.TryParse(input, out j))

                {

                    scratchpad += (j/10f);

                }

            }

        }

​

        if (input == "ENTER")

        {

            if (odocmode == 0)

            {

                oc = scratchpad;

                Console.WriteLine("OC = " + oc.ToString());

            }

            else if (odocmode == 1)

            {

                od = scratchpad;

                Console.WriteLine("OD = " + od.ToString());

            }

​

            scratchpad = 0;

            decimalmode = false;

        }

​

        if (input == "CLEAR")

        {

            scratchpad = 0;

            decimalmode = false;

        }

​

        if (input == "C")

        {

            odocmode = 0;

        }

​

        if (input == "D")

        {

            odocmode = 1;

        }

​

        if (input == ".")

        {

            decimalmode = true;

        }

​

        Console.WriteLine(scratchpad.ToString());

    }

}