using System;

public class Program

{

    public static void Main()

    {

        TestSwitch(10,20,'+');

    }

    public static void TestSwitch(int op1, int op2, Char opr)

    {

        int result;

        switch (opr)

        {

            case'+':

                result = op1 + op2;

                break;

            case'-':

                result = op1 - op2;

                break;

            case'*':

                result = op1 * op2;

                break;

            case'/':

                result = op1 / op2;

                break;

            default: 

                Console.WriteLine("Unknown Operator");

                return; 

        }

        Console.WriteLine("Result:{0}", result);

                return;

    }

}

​