Enum with switch pattern in C Sharp (C#) - Mini Project: Build & Apply

Enum with switch pattern

📖 Scenario: You are creating a simple program to describe different weather conditions using an enum. You want to print a message based on the weather type.

🎯 Goal: Build a program that uses an enum for weather types and a switch expression to print a message for each weather.

📋 What You'll Learn

Create an enum called Weather with values Sunny, Rainy, Cloudy, and Snowy

Create a variable today of type Weather and set it to Weather.Sunny

Use a switch expression on today to get a message string

Print the message string

💡 Why This Matters

🌍 Real World

Enums and switch expressions are common in programs that need to handle fixed categories like weather, traffic lights, or user roles.

💼 Career

Understanding enums and switch expressions helps you write clear and maintainable code in many software development jobs.

1

Create the Weather enum

Create an enum called Weather with these exact values: Sunny, Rainy, Cloudy, and Snowy.

C Sharp (C#)

# Your code here

Hint

An enum groups related named values. Use enum Weather { Sunny, Rainy, Cloudy, Snowy }.

2

Create a variable for today's weather

Create a variable called today of type Weather and set it to Weather.Sunny.

C Sharp (C#)

enum Weather
{
    Sunny,
    Rainy,
    Cloudy,
    Snowy
}

// Your code here

Hint

Declare Weather today = Weather.Sunny; to set the current weather.

3

Use a switch expression to get a message

Create a string variable called message and assign it the result of a switch expression on today. Use these exact cases:
Weather.Sunny => "It's a bright sunny day!"
Weather.Rainy => "Don't forget your umbrella."
Weather.Cloudy => "It might rain later."
Weather.Snowy => "Time to build a snowman!"

C Sharp (C#)

enum Weather
{
    Sunny,
    Rainy,
    Cloudy,
    Snowy
}

Weather today = Weather.Sunny;

// Your code here

Hint

Use a switch expression with today switch { ... } to assign message.

4

Print the message

Write a Console.WriteLine statement to print the message variable.

C Sharp (C#)

enum Weather
{
    Sunny,
    Rainy,
    Cloudy,
    Snowy
}

Weather today = Weather.Sunny;

string message = today switch
{
    Weather.Sunny => "It's a bright sunny day!",
    Weather.Rainy => "Don't forget your umbrella.",
    Weather.Cloudy => "It might rain later.",
    Weather.Snowy => "Time to build a snowman!",
    _ => "Unknown weather"
};

// Your code here

Hint

Use Console.WriteLine(message); to show the message on screen.

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