1 using System; 2  3 public class Operation 4 { 5     public static double GetResult(double numberA, double numberB, string operate) 6     { 7         double result = 0d; 8         switch (operate) 9         {10             case "+":11                 result = numberA + numberB;12                 break;13             case "-":14                 result = numberA - numberB;15                 break;16             case "*":17                 result = numberA * numberB;18                 break;19             case "/":20                 result = numberA / numberB;21                 break;22         }23         return result;24     }25 26 27     class Program28     {29         public static void Main(string[] args)30         {31             Console.Write("Please input numberA: ");32             string strNumberA = Console.ReadLine();33             Console.Write("Please select operate(+ - * /): ");34             string strOperate = Console.ReadLine();35             Console.Write("Please input numberB: ");36             string strNumberB = Console.ReadLine();37             string strResult = "";38             strResult = Convert.ToString(Operation.GetResult(Convert.ToDouble(strNumberA),Convert.ToDouble(strNumberB), strOperate));39             Console.WriteLine("Result is :" + strResult);40             Console.ReadLine();41             Console.Write("Press any key to continue . . . ");42             Console.ReadKey(true);43         }44     }45 }