static void Main(string[] args) { bool calc = false; System.Console.WriteLine("Give me a type of calculation from 1 to 3"); System.Console.WriteLine("1. sum"); System.Console.WriteLine("2. sub"); System.Console.WriteLine("3. mult"); int result = int.Parse(System.Console.ReadLine()); System.Console.WriteLine("Give me the first number"); int Fnum = int.Parse(System.Console.ReadLine()); System.Console.WriteLine("Give me the Second number"); int Snum = int.Parse(System.Console.ReadLine()); switch (result) { case 1: result = Calculation.Sum(Fnum, Snum); calc = true; break; case 2: result = Calculation.Sub(Fnum, Snum); calc = true; break; case 3: result = Calculation.Mult(Fnum, Snum); calc = true; break; default: System.Console.WriteLine("calculation do not exist"); break; } if (calc) { System.Console.WriteLine(result); } }