Why enums are needed in C Sharp (C#) - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare an enum named Days.

C Sharp (C#)

enum [1] { Sunday, Monday, Tuesday }

Drag options to blanks, or click blank then click option'

AMonths

BWeek

CDays

DColors

Attempts:

3 left

💡 Hint

Common Mistakes

Using a name unrelated to the values like Months or Colors.

Leaving the enum name blank.

The enum name should be Days to represent days of the week.

2fill in blank

medium

Complete the code to assign the enum value Monday to variable today.

C Sharp (C#)

Days today = Days.[1];

Drag options to blanks, or click blank then click option'

ASunday

BMonday

CFriday

DTuesday

Attempts:

3 left

💡 Hint

Common Mistakes

Using a day not in the enum like Friday.

Using the enum name without the member.

To assign Monday, use Days.Monday.

3fill in blank

hard

Fix the error in the code to compare enum values correctly.

C Sharp (C#)

if (today == Days.[1]) { Console.WriteLine("It's Monday"); }

Drag options to blanks, or click blank then click option'

Amonday

BMon

CMONDAY

DMonday

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase or abbreviated names that don't match the enum.

Using strings instead of enum members.

Enum members are case-sensitive and must match exactly, so use Monday.

4fill in blank

hard

Fill both blanks to create a switch statement that prints the day name.

C Sharp (C#)

switch (today) {
  case Days.[1]:
    Console.WriteLine("Sunday");
    break;
  case Days.[2]:
    Console.WriteLine("Monday");
    break;
}

Drag options to blanks, or click blank then click option'

ASunday

BMonday

CTuesday

DFriday

Attempts:

3 left

💡 Hint

Common Mistakes

Using days not declared in the enum like Friday.

Using lowercase or abbreviated names.

The switch cases must match the enum members Sunday and Monday.

5fill in blank

hard

Fill all three blanks to create a dictionary mapping enum days to their short names.

C Sharp (C#)

var dayShortNames = new Dictionary<Days, string> {
  { Days.[1], "Sun" },
  { Days.[2], "Mon" },
  { Days.[3], "Tue" }
};

Drag options to blanks, or click blank then click option'

ASunday

BMonday

CTuesday

DFriday

Attempts:

3 left

💡 Hint

Common Mistakes

Including days not in the enum like Friday.

Mismatching enum members and short names.

The dictionary keys must be enum members Sunday, Monday, and Tuesday to match the short names.

Practice

1. Why do we use enum types in C#?

easy

A. To create variables that can hold any data type

B. To group related named constants for better code clarity

C. To perform mathematical calculations faster

D. To store large amounts of text data efficiently

Solution

1. Step 1: Understand the purpose of enums

   Enums group related named constants, making code easier to read and maintain.

2. Step 2: Compare other options

   Other options describe unrelated uses like variable types or data storage, which enums do not do.

3. Final Answer:

   To group related named constants for better code clarity -> Option B

4. Quick Check:

   Enums = group named constants [OK]

Hint: Enums group related names, not data or calculations [OK]

Common Mistakes:

• Thinking enums store any data type
• Confusing enums with variables or arrays
• Assuming enums improve performance directly

2. Which of the following is the correct way to declare an enum in C#?

easy

A. enum Colors = (Red, Green, Blue);

B. enum Colors { 'Red', 'Green', 'Blue' };

C. enum Colors: Red, Green, Blue;

D. enum Colors { Red, Green, Blue };

Solution

1. Step 1: Recall enum declaration syntax

   In C#, enums are declared with enum Name { Value1, Value2, ... } syntax.

2. Step 2: Check each option

   enum Colors { Red, Green, Blue }; matches correct syntax; others use invalid symbols or punctuation.

3. Final Answer:

   enum Colors { Red, Green, Blue }; -> Option D

4. Quick Check:

   Correct enum syntax = enum Colors { Red, Green, Blue }; [OK]

Hint: Use curly braces and commas without quotes for enum values [OK]

Common Mistakes:

• Using parentheses or equal signs instead of braces
• Putting quotes around enum names
• Using colons incorrectly in enum declaration

3. What will be the output of this C# code?

enum Day { Sun, Mon, Tue }
Day today = Day.Mon;
Console.WriteLine((int)today);

medium

A. 1

B. 0

C. Mon

D. Error

Solution

1. Step 1: Understand enum default values

   By default, enum values start at 0 and increase by 1. So Sun=0, Mon=1, Tue=2.

2. Step 2: Cast enum to int

   Casting Day.Mon to int gives 1, which is printed.

3. Final Answer:

   1 -> Option A

4. Quick Check:

   Day.Mon = 1 as int [OK]

Hint: Enum values start at 0 by default, increment by 1 [OK]

Common Mistakes:

• Expecting enum name instead of int value
• Assuming enums start at 1 by default
• Forgetting to cast enum to int for numeric output

4. Identify the error in this enum usage:

enum Status { Active = 1, Inactive = 2 }
Status s = 3;
Console.WriteLine(s);

medium

A. Cannot assign integer 3 to enum Status variable

B. Enum values must start at 0

C. Missing semicolon after enum declaration

D. Enum names cannot be capitalized

Solution

1. Step 1: Check enum assignment rules

   You cannot assign an integer value not defined in the enum to an enum variable directly.

2. Step 2: Analyze the code

   Assigning 3 to Status s is invalid because 3 is not a defined enum value.

3. Final Answer:

   Cannot assign integer 3 to enum Status variable -> Option A

4. Quick Check:

   Enum variable must hold defined enum values [OK]

Hint: Enum variables accept only defined enum values [OK]

Common Mistakes:

• Assigning undefined integers to enum variables
• Thinking enum values must start at zero
• Ignoring compiler errors about enum assignments

5. You want to represent the four seasons in your program using enums. Which benefit does using an enum provide over using plain integers or strings?

hard

A. Enums use less memory than integers

B. Enums automatically translate to user-friendly text

C. Enums prevent invalid values and improve code readability

D. Enums allow storing multiple values in one variable

Solution

1. Step 1: Understand enum advantages

   Enums group named constants and restrict values to valid options, improving readability and reducing errors.

2. Step 2: Evaluate other options

   Enums do not automatically translate text, save memory over ints, or store multiple values in one variable.

3. Final Answer:

   Enums prevent invalid values and improve code readability -> Option C

4. Quick Check:

   Enums = safer, clearer named constants [OK]

Hint: Enums limit values to valid names, avoiding mistakes [OK]

Common Mistakes:

• Believing enums convert to user text automatically
• Assuming enums save memory compared to ints
• Thinking enums can hold multiple values at once