using System;

​

public class Program

{

    enum Planets

    {

        Mercury,

        Venus,

        Earth,

        Mars,

        Jupiter

    }

​

    enum Numbers { One = 1, Two = 2, Three = 3, Four = 4, Five = 5 }

​

    public static void Main()

    {

        Planets planet;

        planet = Planets.Mercury;

        Console.WriteLine("\n----------ToString()----------\n");

        string strPlanet = planet.ToString();

        Console.WriteLine(strPlanet);

        Console.WriteLine("\n----------Enum.IsDefined----------\n");

        Console.WriteLine(Enum.IsDefined(typeof(Planets), Planets.Mercury)); // True

        Console.WriteLine(Enum.IsDefined(typeof(Planets), "Earth")); // True

        Console.WriteLine(Enum.IsDefined(typeof(Planets), "Neptune")); // False

        Console.WriteLine(Enum.IsDefined(typeof(Planets), 1)); // True

        Console.WriteLine(Enum.IsDefined(typeof(Planets), 20)); // False

        Console.WriteLine("\n----------Enum.TryParse with Enum.IsDefined----------\n");

        Planets planet5;

        if (Enum.TryParse<Planets>("2", out planet5))

        {

            if (Enum.IsDefined(typeof(Planets), planet5))

                Console.WriteLine($"{planet5} found.");

            else

                Console.WriteLine("Unknow Planet :(");

        }

​

        Console.WriteLine("\n----------Operators----------\n");

        // //==, !=, <, >, <=, >=, binary +, binary -, ^, &, |, ~, and ++ and –

        Console.WriteLine($"== : {Numbers.One == Numbers.Three}"); // False

        Console.WriteLine($"!= : {Numbers.One != Numbers.Two}"); // True

        Console.WriteLine($">= : {Numbers.Four >= Numbers.Five}"); // False

        Console.WriteLine($"<= : {Numbers.Two <= Numbers.Four}"); // True

        Console.WriteLine($"> : {Numbers.Four > Numbers.Three}"); // True

        Console.WriteLine($"< : {Numbers.Five < Numbers.One}"); // False

​

        Console.WriteLine($"- : {Numbers.Five - Numbers.One}"); // 4

        Console.WriteLine($"& : {Numbers.Five & Numbers.One}"); // One

        Console.WriteLine($"| : {Numbers.Five | Numbers.One}"); // Five

​

        int Three = (int)Numbers.Three;

        int Four = (int)Numbers.Four;

​

        Console.WriteLine($"Three++ : {Three++}"); // 3

        Console.WriteLine($"++Three : {++Three}"); // 5

        Console.WriteLine($"Four-- : {Four--}"); // 4

        Console.WriteLine($"--Four : {--Four}"); // 2

        Console.WriteLine($"~Four : {~Four}"); // -3

    }

}