Enum declaration syntax in C Sharp (C#) - Step-by-Step Execution

Concept Flow - Enum declaration syntax

Start Enum Declaration

↓

Write 'enum' keyword

↓

Name the Enum

↓

Open curly brace '{'

↓

List enum members

↓

Close curly brace '}'

↓

Enum declared successfully

This flow shows the steps to declare an enum: start with the keyword, name it, list members inside braces, then finish.

Execution Sample

C Sharp (C#)

enum Days {
    Sunday,
    Monday,
    Tuesday
}

Declares an enum named Days with three members: Sunday, Monday, and Tuesday.

Execution Table

Step	Code Part	Action	Result
1	enum Days	Recognize enum keyword and name	Prepare to declare enum named Days
2	{	Open enum body	Start listing members
3	Sunday,	Add member Sunday	Sunday assigned value 0 by default
4	Monday,	Add member Monday	Monday assigned value 1 by default
5	Tuesday	Add member Tuesday	Tuesday assigned value 2 by default
6	}	Close enum body	Enum Days declared with 3 members

💡 All enum members listed and enum declaration closed with '}'

Variable Tracker

Variable	Start	After 1	After 2	After 3	Final
Days.Sunday	undefined	0	0	0	0
Days.Monday	undefined	undefined	1	1	1
Days.Tuesday	undefined	undefined	undefined	2	2

Key Moments - 3 Insights

Why does Sunday get the value 0 automatically?

By default, enum members start at 0 and increase by 1 for each member, as shown in execution_table rows 3 to 5.

What happens if I forget the closing brace '}'?

The enum declaration is incomplete and will cause a syntax error; execution_table row 6 shows the importance of closing the enum.

Can enum members have explicit values?

Yes, but in this example, values are assigned automatically starting at 0, as seen in variable_tracker.

Visual Quiz - 3 Questions

Look at the execution_table, what value is assigned to Monday?

A 0

B 2

C 1

D undefined

💡 Hint

Check execution_table row 4 where Monday is assigned value 1.

At which step does the enum declaration close?

A Step 6

B Step 4

C Step 3

D Step 2

💡 Hint

Look at execution_table row 6 where '}' closes the enum.

If you add a new member after Tuesday, what value will it have by default?

A 2

B 3

C 0

D Undefined

💡 Hint

See variable_tracker: values increment by 1 for each new member.

Concept Snapshot

Enum declaration syntax in C#:
enum EnumName {
  Member1, // default 0
  Member2, // default 1
  Member3  // default 2
}
Members auto-increment starting at 0 unless assigned explicitly.

Full Transcript

This visual execution shows how to declare an enum in C#. First, write the keyword 'enum' followed by the enum name. Then open curly braces and list the members separated by commas. Each member gets an automatic integer value starting at 0 and increasing by 1. Finally, close the braces to complete the declaration. The execution table traces each step, showing how members get assigned values. The variable tracker shows the values of each member after each step. Key moments clarify common confusions like default values and the need for closing braces. The quiz tests understanding of member values and declaration steps.

Practice

1. What is the purpose of an enum in C#?

easy

A. To group related named constants together

B. To create a new class type

C. To define a method

D. To declare a variable

Solution

1. Step 1: Understand enum concept

   An enum groups related named constants to make code clearer.

2. Step 2: Compare with other options

   Enums are not classes, methods, or variables but a special type for constants.

3. Final Answer:

   To group related named constants together -> Option A

4. Quick Check:

   Enum = group constants [OK]

Hint: Enums group named constants, not variables or methods [OK]

Common Mistakes:

• Thinking enum is a class
• Confusing enum with method or variable
• Assuming enum holds variable data

2. Which of the following is the correct syntax to declare an enum named Days with members Monday and Tuesday?

easy

A. enum Days: Monday, Tuesday;

B. enum Days = { Monday, Tuesday };

C. enum Days { Monday, Tuesday };

D. enum Days (Monday, Tuesday);

Solution

1. Step 1: Recall enum declaration syntax

   Enums use curly braces with members separated by commas, no equals or parentheses.

2. Step 2: Check each option

   enum Days { Monday, Tuesday }; matches correct syntax: enum Days { Monday, Tuesday };.

3. Final Answer:

   enum Days { Monday, Tuesday }; -> Option C

4. Quick Check:

   Enum syntax uses braces and commas [OK]

Hint: Use braces and commas for enum members [OK]

Common Mistakes:

• Using equals sign (=) after enum name
• Using parentheses instead of braces
• Using colon (:) instead of opening brace

3. What is the output of this code?

enum Color { Red, Green, Blue };
Console.WriteLine((int)Color.Green);

medium

A. 0

B. 1

C. 2

D. Green

Solution

1. Step 1: Understand default enum values

   Enum members start at 0 by default: Red=0, Green=1, Blue=2.

2. Step 2: Cast enum member to int

   Printing (int)Color.Green outputs its numeric value 1.

3. Final Answer:

   1 -> Option B

4. Quick Check:

   Green = 1 by default [OK]

Hint: Enum members start at 0 unless assigned [OK]

Common Mistakes:

• Assuming first member starts at 1
• Printing enum name instead of int value
• Confusing enum member order

4. Identify the error in this enum declaration:

enum Status
{
  Started = 1,
  InProgress = 2,
  Completed = "Done"
};

medium

A. Enum members must be separated by semicolons

B. Missing semicolon after enum declaration

C. Enum name must be lowercase

D. Enum members cannot have string values

Solution

1. Step 1: Check enum member value types

   Enum members must be integral types (int, byte, etc.), not strings.

2. Step 2: Analyze the given code

   "Completed = \"Done\"" assigns a string, which is invalid.

3. Final Answer:

   Enum members cannot have string values -> Option D

4. Quick Check:

   Enum values must be integers [OK]

Hint: Enum values must be integers, not strings [OK]

Common Mistakes:

• Assigning string values to enum members
• Thinking semicolon is required after enum
• Assuming enum names must be lowercase

5. How can you declare an enum Priority with members Low=1, Medium=5, and High=10 so that the values are not sequential?

hard

A. enum Priority { Low = 1, Medium = 5, High = 10 };

B. enum Priority { Low, Medium, High }

C. enum Priority { Low = 1; Medium = 5; High = 10 }

D. enum Priority = { Low = 1, Medium = 5, High = 10 }

Solution

1. Step 1: Assign explicit values to enum members

   To set custom values, assign each member an integer with = and commas between.

2. Step 2: Check syntax correctness

   enum Priority { Low = 1, Medium = 5, High = 10 }; uses correct syntax with commas and explicit values.

3. Final Answer:

   enum Priority { Low = 1, Medium = 5, High = 10 }; -> Option A

4. Quick Check:

   Use = and commas for custom enum values [OK]

Hint: Assign values with = and separate members by commas [OK]

Common Mistakes:

• Using semicolons instead of commas
• Omitting explicit values for custom numbers
• Using equals sign after enum name