static void Main(string[] args) { double hrv; do { Console.WriteLine("Enter how much hryvnas you have: "); hrv = Convert.ToDouble(Console.ReadLine()); } while (hrv <= 0); double usd; do { Console.WriteLine("Enter convert course in dollars: "); usd = Convert.ToDouble(Console.ReadLine()); } while (usd <= 0); double eur; do { Console.WriteLine("Enter convert course in euros: "); eur = Convert.ToDouble(Console.ReadLine()); } while (eur <= 0); Converter conv = new Converter(usd, eur); conv.ConvertFromDollars(hrv); conv.ConvertFromEuros(hrv); conv.ConvertToDollars(hrv); conv.ConverttoEuros(hrv); Console.ReadKey(); }