เครื่องคิดเลขด้วยนิพจน์ switch

using System;
class Program
{
    static double Calculate(double a, string op, double b) => op switch
    {
        "+" => a + b, "-" => a - b, "*" => a * b,
        "/" when b != 0 => a / b,
        _ => throw new ArgumentException("Unsupported operation")
    };
    static void Main() => Console.WriteLine(Calculate(6, "*", 7));
}