Why Enums?

Why Enums.cs

using System;
using System.Collections;

/* Enumeration Notes
 * 
 * Enums are value types
 * 
 * Enums are strongly-typed constants
 *      An explicit cast is needed to convert from enum type to an integral type and vice-versa.
 *      An enum of one type cannot be implicitly assigned to an enum of another type -- even though the underlying value of their members are the same
 *      
 * The default underlying value for an enum is an integer
 * You CAN customize the underlying type and value of an enum
 * 
 * If a program uses a set of integral numbers, one might consider replacing them with enums.
 * 
 * Enums promote Readability and Maintainability
 *
 * Why Enums?
 *      In the first region, the code will not use Enums
 *      In the second region, the code will be modified to use Enums
 * 
 */


#region Without Enums
class NoEnums
{
    public static void WithoutEnums()
    {
        var customers = new Customer[3];

        customers[0] = new Customer
        {
            Name = "Derrik",
            Gender = 1 //without documentation, how would we know what "1" even means? 
        };
        customers[1] = new Customer
        {
            Name = "Anthony",
            Gender = 0
        };
        customers[2] = new Customer
        {
            Name = "Harold",
            Gender = 2
        };

        foreach (var customer in customers)
        {
            Console.WriteLine("Name: {0} and Gender: {1}",customer.Name, GetGender(customer.Gender));
        }
    }

    public static string GetGender(int gender)
    //this is bad, imagine if there were many cases throughout the program. it would be very hard to track which integer corrsponds to which value. 
    {
        switch (gender)
        {
            case 0:
                return "Unknown";
            case 1:
                return "Male";
            case 3:
                return "Female";
            default:
                return "Invalid data";
        }
    }
}


public class Customer
{
    public string Name { get; set; }
    public int Gender { get; set; }
}
#endregion

#region With Enums
class UsingEnums
{
    public static void Main()
    {
        int[] genderValues = (int[]) Enum.GetValues(typeof (Gender));

        foreach (int value in genderValues)
        {
            Console.WriteLine(value);
        }

        string[] genderNames = (string[]) Enum.GetNames(typeof (Gender));
        {
            foreach (string value in genderNames)
            {
                Console.WriteLine(value);
            }
        }
        
        Console.ReadKey();
    }
}

public enum Gender //defaults to int
{
    Unknown, //the underlying value, by default, is an int of 0. If we set Unknown = 1, then Male and Female will become subsequent values (2, 3 respectively)
    Male,
    Female
}

#endregion