Enums

Let’s dive into enums in C#.

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📌 1. What is an Enum?

• Enum (short for enumeration) is a special value type that represents a set of named constants.

• It improves readability and type safety compared to using plain integers or strings.

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📌 2. Basic Syntax

public enum Day
{
    Sunday,
    Monday,
    Tuesday,
    Wednesday,
    Thursday,
    Friday,
    Saturday
}

• By default, the underlying type is int.

• The first value (Sunday) is 0, next (Monday) is 1, and so on.

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📌 3. Using Enums

class Program
{
    static void Main()
    {
        Day today = Day.Wednesday;
 
        Console.WriteLine(today);         // Output: Wednesday
        Console.WriteLine((int)today);    // Output: 3
    }
}

• You can cast enum values to int to see the underlying number.

• You can also cast integers to enums:

Day someDay = (Day)5;
Console.WriteLine(someDay); // Output: Friday

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📌 4. Assigning Custom Values

public enum ErrorCode
{
    None = 0,
    NotFound = 404,
    ServerError = 500,
    Unauthorized = 401
}

• Each constant can have an explicit value.

• Useful for mapping to status codes, flags, or other numeric identifiers.

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📌 5. Enum Underlying Types

• You can specify the underlying type (must be integral):

public enum ByteEnum : byte
{
    A = 1,
    B = 2
}

• Default is int.

• Other allowed types: byte, sbyte, short, ushort, int, uint, long, ulong.

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📌 6. Flags Enums

• For combinations of values (bitwise operations), use [Flags] attribute:

[Flags]
public enum FileAccess
{
    Read = 1,
    Write = 2,
    Execute = 4
}
 
class Program
{
    static void Main()
    {
        FileAccess permissions = FileAccess.Read | FileAccess.Write;
        Console.WriteLine(permissions); // Output: Read, Write
 
        bool canWrite = (permissions & FileAccess.Write) == FileAccess.Write;
        Console.WriteLine(canWrite);    // Output: True
    }
}

• [Flags] makes the enum printable as a combination of names instead of a number.

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📌 7. Summary

Feature	Notes
Enum	Named constants
Default type	int
Custom underlying type	byte, long, etc.
Custom values	Yes, assign manually
Flags	Combine multiple values with bitwise operators

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✅ In short:
Enums make your code more readable, maintainable, and type-safe when working with fixed sets of values.
Use [Flags] when you need combinations of values.

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If you want, I can also create a cheat sheet comparing Enums vs Const vs Static readonly in C# — it helps decide when to use which.

Do you want me to make that?