using System;

public class Program

{

    static string input;

    static int iNum1;

    static int iNum2;

    static double result;

    public static void Main()

    {

        Console.WriteLine("--------Calculator--------");

        Console.WriteLine("Select what kind of calculation you want to do: \n1. - for addition \n2. - for subtraction \n3. - for division \n4. - for multiplication");

        int iSelection;

        bool CorrectInput = int.TryParse(Console.ReadLine(), out iSelection);

        if(CorrectInput)

        {

            switch(iSelection)

            {

                case 1:

                    result = AdditionMethod();

                    break;

                case 2:

                    result = SubtractionMethod();

                    break;

                case 3:

                    result = DivisionMethod();

                    break;

                case 4:

                    result = MultiplicationMethod();

                    break;

                default:

                    Console.WriteLine("Invalid Selection!");

                    break;

            }

            Console.WriteLine("Result: " + result.ToString("0.00"));

        }

        else 

            Console.WriteLine("Invalid Input");

    }

    static double AdditionMethod()

    {

        Console.WriteLine("You Selected Addition:");

        Console.Write("Enter First Number: ");

        iNum1 = int.Parse(Console.ReadLine());

        Console.Write("Enter Second Number: ");

        iNum2 = int.Parse(Console.ReadLine());

        return  iNum1 + iNum2;

    }

    static double SubtractionMethod()

    {

        Console.WriteLine("You Selected Subtraction:");

        Console.Write("Enter First Number: ");

        iNum1 = int.Parse(Console.ReadLine());

        Console.Write("Enter Second Number: ");

        iNum2 = int.Parse(Console.ReadLine());

        return iNum1 - iNum2;

    }

    static double DivisionMethod()

    {

        Console.WriteLine("You Selected Division:");

        Console.Write("Enter First Number: ");

        iNum1 = int.Parse(Console.ReadLine());

        Console.Write("Enter Second Number: ");

        iNum2 = int.Parse(Console.ReadLine());

        if(iNum2 == 0)

        {

            Console.WriteLine("Cannot divide by zero!");

            return 0;

        }

        return (iNum1 * 1.0) / (iNum2 * 1.0);

    }

    static double MultiplicationMethod()

    {

        Console.WriteLine("You Selected Multiplication:");

        Console.Write("Enter First Number: ");

        iNum1 = int.Parse(Console.ReadLine());

        Console.Write("Enter Second Number: ");

        iNum2 = int.Parse(Console.ReadLine());

        return iNum1 * iNum2;

    }

}