Calculatrice

mon code : 

using System;

namespace Giraffe
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("insert number1");
            double num1 = Convert.ToDouble(Console.ReadLine());

            Console.WriteLine("insert operator");
            string op = Console.ReadLine();

            Console.WriteLine("insert number2");
            double num2 = Convert.ToDouble(Console.ReadLine());
         
            if (op == "+")
            {
                double result = num1 + num2;
            }

            else if(op == "-")
            {
                double result = num1 - num2;
            }

            else if (op == "*")
            {
                double result = num1 * num2;
            }

            else if (op == "/")
            {
                double result = num1 / num2;
            }


            Console.WriteLine(result);


        }
     
    }
}