using System;

public class Program

{

    public static void Main()

    {

        int number;

        Console.WriteLine("Hello! Please choose the menu :)");

        Console.WriteLine("================================");

        Console.WriteLine("        1:convert from kg to g");

        Console.WriteLine("        2:convert from g to kg");

        Console.WriteLine("        3:exit");

        Console.WriteLine("================================");

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

        switch(number)

     {

         case 1:

             {

                 Convertkgtog();

                 break;

             }

         case 2:

             {

                 double g,kg;

                 Console.Write("ENTER THE VALUE:");

                 g=double.Parse(Console.ReadLine());

                 kg=Convertgtokg(g);

                 Console.WriteLine("The answer is {0}kg",kg);

                 break;

             }

         case 3:

             {

                 Console.WriteLine("THANKYOU");

                 break;

             }

         default:

             Console.WriteLine("Follow The Menu Please!!!");

             break;

     }

    }

    public static void Convertkgtog()

    {

        double g,kg;

        Console.Write("ENTER NUMBER:");

        kg=double.Parse(Console.ReadLine());

        g=kg*1000;

        Console.WriteLine("The answer is {0}g",g);

    }

    public static double 

        Convertgtokg(double kg)

    {

        kg=kg/1000;

        return kg;

    }

}

​