using System;

public class Program

{

    public static void Main()

    {

        double n1;

            double n2;

            string op;

            double r;

            Console.WriteLine("Ingrese un numero: ");

            n1 = Double.Parse(Console.ReadLine());

            Console.WriteLine("Ingrese un numero: ");

            n2 = Double.Parse(Console.ReadLine());

            Console.WriteLine("Ingrese operador numerico: ");

            op = Console.ReadLine();

            switch (op) {

            case "+":

                r = n1+n2;

                break;

            case "-":

                r = n1-n2;

                break;

            case "*":

                r = n1*n2;

                break;

            case "^":

                r = Math.Pow(n1,n2);

                break;

            default: r = 0;

                    break;

            }

            Console.WriteLine("El resultado es:"+r);

        }

    }

​