using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("What would you like to convert? \n1.C TO F \n2. F TO C ");

        int iChoice =0;

        double dCelsius = 0;

        double dFahrenheit =0;

        if(int.TryParse(Console.ReadLine(), out iChoice))

        {

            switch(iChoice)

            {

                case 1:

                    Console.Write("Enter a temp in C: ");

                    if(double.TryParse(Console.ReadLine(), out dCelsius))

                    {

                        dCelsius = CelsiusToFahrenheit( ref dCelsius);

                        Console.WriteLine("the temp in F is : "+ dCelsius +"F");

                    }

                    break;

                case 2:

                    Console.Write("Enter a temp in F ");

                    if(double.TryParse(Console.ReadLine(), out dFahrenheit))

                    {

                        dFahrenheit=  FahrenheitToCelsius( ref dFahrenheit);

                        Console.WriteLine("the temp in C is : "+ dFahrenheit +"c");

                        Console.WriteLine(dFahrenheit);

                    }

                    break;

            }

        }

        else

        {

            Console.WriteLine("invalid input");

        }

    }

    static double CelsiusToFahrenheit(ref double _celsius)

    {

        return (_celsius * 9/5)+32;

    }

    static double FahrenheitToCelsius(ref double _fahrenheit)

    {

        return (_fahrenheit - 32) *5/9;

    }

}