Enum with switch pattern in C Sharp (C#) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare an enum named Color.

C Sharp (C#)

enum [1] { Red, Green, Blue }

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

Acolor

BColors

CColor

DColour

Attempts:

3 left

💡 Hint

Common Mistakes

Using plural form like 'Colors' instead of singular 'Color'.

Using lowercase names which is not a C# convention.

The enum is named Color to represent colors.

2fill in blank

medium

Complete the switch expression to return the string name of the color.

C Sharp (C#)

string GetColorName(Color color) => color switch { Color.Red => [1], _ => "Unknown" };

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

ARed

B"Red"

C'Red'

DRed.ToString()

Attempts:

3 left

💡 Hint

Common Mistakes

Returning the enum member itself instead of a string.

Using single quotes which are for characters, not strings.

The switch expression returns the string "Red" for Color.Red.

3fill in blank

hard

Fix the error in the switch expression to handle all enum values.

C Sharp (C#)

string GetColorName(Color color) => color switch { Color.Red => "Red", Color.Green => [1], Color.Blue => "Blue", _ => "Unknown" };

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

Acolor.ToString()

BGreen

C'Green'

D"Green"

Attempts:

3 left

💡 Hint

Common Mistakes

Returning the enum member instead of a string.

Using single quotes instead of double quotes.

The switch expression must return the string "Green" for Color.Green.

4fill in blank

hard

Fill both blanks to complete the switch expression that returns a message for each color.

C Sharp (C#)

string GetColorMessage(Color color) => color switch { Color.Red => [1], Color.Green => [2], _ => "Color not recognized" };

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

A"Stop!"

B"Go!"

C"Wait!"

D"Slow down!"

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up messages for colors.

Forgetting to use quotes around the messages.

The messages correspond to the colors: Red means "Stop!" and Green means "Go!".

5fill in blank

hard

Fill all three blanks to create a switch expression that returns the color's hex code.

C Sharp (C#)

string GetColorHex(Color color) => color switch { Color.Red => [1], Color.Green => [2], Color.Blue => [3], _ => "#000000" };

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

A"#FF0000"

B"#00FF00"

C"#0000FF"

D"#FFFFFF"

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up hex codes for colors.

Using quotes incorrectly or missing them.

The hex codes represent the colors: Red is #FF0000, Green is #00FF00, and Blue is #0000FF.

Practice

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

easy

A. To give meaningful names to a set of related constant values

B. To create a new class with methods

C. To store multiple unrelated variables

D. To define a method that returns multiple values

Solution

1. Step 1: Understand what enums represent

   Enums are used to name a fixed set of related constants, like days of the week or colors.

2. Step 2: Compare options with enum purpose

   Only To give meaningful names to a set of related constant values correctly describes enums as naming related constant values.

3. Final Answer:

   To give meaningful names to a set of related constant values -> Option A

4. Quick Check:

   Enum = Named constants [OK]

Hint: Enums name fixed sets of values clearly [OK]

Common Mistakes:

• Thinking enums create classes
• Confusing enums with variables
• Assuming enums store unrelated data

2. Which of the following is the correct syntax to declare an enum named Day with values Monday, Tuesday, and Wednesday?

easy

A. enum Day (Monday, Tuesday, Wednesday);

B. enum Day { Monday, Tuesday, Wednesday }

C. enum Day: Monday, Tuesday, Wednesday;

D. enum Day = { Monday, Tuesday, Wednesday };

Solution

1. Step 1: Recall enum declaration syntax

   In C#, enums are declared with the keyword enum, name, and curly braces listing values separated by commas.

2. Step 2: Match syntax to options

   enum Day { Monday, Tuesday, Wednesday } matches the correct syntax: enum Day { Monday, Tuesday, Wednesday }.

3. Final Answer:

   enum Day { Monday, Tuesday, Wednesday } -> Option B

4. Quick Check:

   Enum syntax uses braces and commas [OK]

Hint: Use braces and commas to list enum values [OK]

Common Mistakes:

• Using equals sign (=) after enum name
• Using colons or parentheses incorrectly
• Missing commas between values

3. Given the enum and switch code below, what will be printed?

enum Color { Red, Green, Blue }

Color c = Color.Green;
switch (c)
{
    case Color.Red:
        Console.WriteLine("Stop");
        break;
    case Color.Green:
        Console.WriteLine("Go");
        break;
    case Color.Blue:
        Console.WriteLine("Wait");
        break;
}

medium

A. Go

B. Stop

C. Wait

D. No output

Solution

1. Step 1: Identify the enum value assigned

   The variable c is assigned Color.Green.

2. Step 2: Follow switch cases for Color.Green

   The switch matches Color.Green and prints "Go".

3. Final Answer:

   Go -> Option A

4. Quick Check:

   Switch on enum Green prints "Go" [OK]

Hint: Match enum value to switch case output [OK]

Common Mistakes:

• Confusing enum values with strings
• Missing break causing fall-through
• Assuming default case runs without match

4. What is wrong with the following code snippet?

enum Status { Pending, Approved, Rejected }

Status s = Status.Approved;
switch (s)
{
    case Status.Pending:
        Console.WriteLine("Waiting");
    case Status.Approved:
        Console.WriteLine("Accepted");
        break;
    case Status.Rejected:
        Console.WriteLine("Denied");
        break;
}

medium

A. Variable s is not assigned a value

B. Enum values are not declared correctly

C. Switch statement syntax is invalid

D. Missing break after case Status.Pending causes fall-through

Solution

1. Step 1: Check switch cases for breaks

   The case Status.Pending lacks a break;, so execution falls through to the next case.

2. Step 2: Understand fall-through effect

   If s was Status.Pending, it would print both "Waiting" and "Accepted" unintentionally.

3. Final Answer:

   Missing break after case Status.Pending causes fall-through -> Option D

4. Quick Check:

   Each switch case needs a break [OK]

Hint: Always add break after each switch case [OK]

Common Mistakes:

• Forgetting break causes multiple case runs
• Assuming enum declaration is wrong
• Thinking variable is uninitialized

5. You want to write a method that takes an enum Season with values Spring, Summer, Fall, Winter and returns a string describing the typical weather. Which switch expression correctly returns "Warm" for Summer and Spring, "Cool" for Fall, and "Cold" for Winter?

hard

A. return season switch {
Season.Spring, Season.Summer => "Warm",
Season.Fall => "Cold",
Season.Winter => "Cool"
};

B. switch (season) {
case Season.Spring:
case Season.Summer:
return "Warm";
case Season.Fall:
return "Cool";
case Season.Winter:
return "Cold";
default:
return "Unknown";
}

C. return season switch {
Season.Spring => "Warm",
Season.Summer => "Warm",
Season.Fall => "Cool",
Season.Winter => "Cold",
_ => "Unknown"
};

D. switch (season) {
case Season.Spring:
return "Warm";
case Season.Summer:
return "Cool";
case Season.Fall:
return "Cold";
case Season.Winter:
return "Cold";
}

Solution

1. Step 1: Check switch expression syntax

   return season switch { Season.Spring => "Warm", Season.Summer => "Warm", Season.Fall => "Cool", Season.Winter => "Cold", _ => "Unknown" }; uses the modern C# switch expression with correct syntax and covers all enum values with correct returns.

2. Step 2: Verify correct mapping of seasons to weather

   Spring and Summer return "Warm", Fall returns "Cool", Winter returns "Cold", and a default case handles unknowns.

3. Final Answer:

   return season switch { Season.Spring => "Warm", Season.Summer => "Warm", Season.Fall => "Cool", Season.Winter => "Cold", _ => "Unknown" }; -> Option C

4. Quick Check:

   Switch expression with correct mappings [OK]

Hint: Use switch expressions for concise enum mapping [OK]

Common Mistakes:

• Using incorrect syntax for multiple values in switch expression
• Mixing return values incorrectly
• Missing default case in switch expression