[Answer]Problem #2 EXAM dotnetstarter.blogspot.com

using System;
using System.Collections.Generic;
using System.Text;
namespace practice
{
    class Program
    {
        static void Main(string[] args)
        {           
            string choice;
            double C;
            double a = 0.55555555555555555555555555555556;
            double F;
            bool repeat = false;
            do
            {
                Console.WriteLine("Menu:");
                Console.WriteLine("[C] Convert from Fahrenheit to Celsius");
                Console.WriteLine("[F] Convert from Celsius to Fahrenheit");
                Console.WriteLine("[X] Exit application");
                Console.Write("Choice: "); repeat = false;
                choice = Console.ReadLine();
                switch (choice)
                {
                    case "c":
                    case "C":
                        {
                            Console.Write("Enter temperature in Fahrenheit: ");
                            choice = Console.ReadLine();
                            if (choice == "")
                            {
                                repeat = true; break;
                            }
                            else
                            {
                                F = double.Parse(choice);
                                C = ((F - 32) * a);
                                Console.WriteLine("Temperature in Celcius: " + C);
                                repeat = true; break;
                            }
                        }
                    case "f":
                    case "F":
                        {
                            Console.Write("Enter temperature in Celsius: ");
                            choice = Console.ReadLine();
                            if (choice == "")
                            {
                                repeat = true; break;
                            }
                            else
                            {
                                C = double.Parse(choice);
                                F = (1.8) * C + 32;
                                Console.WriteLine("Temperature in Fahrenheit: " + F);
                                repeat = true; break;
                            }
                        }
                    case "x":
                    case "X":
                        {
                            Console.WriteLine("BABAY!!!"); break;
                        }
                    default:
                        {
                            Console.WriteLine("Error"); Console.ReadLine();
                            repeat = true; break;
                        }
                }
            } while (repeat == true);
        }
    }
}