Enum declaration syntax in C Sharp (C#) - Mini Project: Build & Apply

Enum declaration syntax

📖 Scenario: Imagine you are creating a simple program to manage the days of the week. You want to use an enum to represent the days so your code is clear and easy to read.

🎯 Goal: You will create an enum named DaysOfWeek with all seven days as its members. Then, you will print one of the days to see how enums work in C#.

📋 What You'll Learn

Create an enum called DaysOfWeek with members: Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday

Create a variable called today of type DaysOfWeek and set it to DaysOfWeek.Wednesday

Print the value of today to the console

💡 Why This Matters

🌍 Real World

Enums are used to represent fixed sets of related constants, like days, months, directions, or states in a program.

💼 Career

Understanding enums helps you write clearer and safer code, which is important in many software development jobs.

1

Create the enum DaysOfWeek

Write an enum declaration named DaysOfWeek with these members exactly: Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday.

C Sharp (C#)

// Declare the enum DaysOfWeek here
// Your code here

Hint

Use the enum keyword followed by the name DaysOfWeek. Inside curly braces, list all days separated by commas.

2

Create a variable today of type DaysOfWeek

Create a variable called today of type DaysOfWeek and set it to DaysOfWeek.Wednesday.

C Sharp (C#)

enum DaysOfWeek
{
    Monday,
    Tuesday,
    Wednesday,
    Thursday,
    Friday,
    Saturday,
    Sunday
}

// Create the variable today and set it to DaysOfWeek.Wednesday
// Your code here

Hint

Use the syntax: DaysOfWeek today = DaysOfWeek.Wednesday;

3

Print the value of today

Write a Console.WriteLine statement to print the value of the variable today.

C Sharp (C#)

enum DaysOfWeek
{
    Monday,
    Tuesday,
    Wednesday,
    Thursday,
    Friday,
    Saturday,
    Sunday
}

DaysOfWeek today = DaysOfWeek.Wednesday;

// Print the value of today
// Your code here

Hint

Use Console.WriteLine(today); to print the enum value.

4

Run the program to see the output

Run the program and observe the output. It should print Wednesday.

C Sharp (C#)

using System;

enum DaysOfWeek
{
    Monday,
    Tuesday,
    Wednesday,
    Thursday,
    Friday,
    Saturday,
    Sunday
}

class Program
{
    static void Main()
    {
        DaysOfWeek today = DaysOfWeek.Wednesday;
        Console.WriteLine(today);
    }
}

// Run the program to see the output

Hint

The program should print Wednesday exactly.

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