Enum with switch pattern in C Sharp (C#) - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of Enum switch expression

What is the output of the following C# code?

C Sharp (C#)

enum TrafficLight { Red, Yellow, Green }

class Program {
    static string GetAction(TrafficLight light) => light switch {
        TrafficLight.Red => "Stop",
        TrafficLight.Yellow => "Caution",
        TrafficLight.Green => "Go",
        _ => "Unknown"
    };

    static void Main() {
        System.Console.WriteLine(GetAction(TrafficLight.Yellow));
    }
}

A Caution

B Go

C Stop

D Unknown

💡 Hint

Look at the switch expression matching the enum value Yellow.

The switch expression matches TrafficLight.Yellow and returns "Caution".

❓ Predict Output

intermediate

Switch expression with default case output

What will this C# program print when run?

C Sharp (C#)

enum Season { Spring, Summer, Autumn, Winter }

class Program {
    static string Describe(Season s) => s switch {
        Season.Spring => "Flowers bloom",
        Season.Summer => "Sun shines",
        _ => "Cold season"
    };

    static void Main() {
        System.Console.WriteLine(Describe(Season.Winter));
    }
}

A Sun shines

B Cold season

C Compilation error

D Flowers bloom

💡 Hint

Check which case matches Season.Winter in the switch expression.

Winter is not explicitly matched, so the default case '_' returns "Cold season".

🔧 Debug

advanced

Identify the error in enum switch pattern

What error will this C# code produce when compiled?

C Sharp (C#)

enum Direction { North, East, South, West }

class Program {
    static string Turn(Direction d) => d switch {
        Direction.North => "Go up",
        Direction.East => "Go right",
        Direction.South => "Go down"
    };

    static void Main() {
        System.Console.WriteLine(Turn(Direction.West));
    }
}

A CS8509: The switch expression does not handle all possible values

B System.InvalidOperationException at runtime

C CS0128: A local variable is already defined

D No error, prints "Go right"

💡 Hint

Check if the switch expression covers all enum values.

The switch expression misses Direction.West and has no default case, causing CS8509 compile error.

❓ Predict Output

advanced

Output of nested switch with enum

What is the output of this C# program?

C Sharp (C#)

enum Mode { Auto, Manual }
enum Status { On, Off }

class Program {
    static string GetMessage(Mode m, Status s) => m switch {
        Mode.Auto => s switch {
            Status.On => "Auto mode ON",
            Status.Off => "Auto mode OFF"
        },
        Mode.Manual => s switch {
            Status.On => "Manual mode ON",
            Status.Off => "Manual mode OFF"
        },
        _ => "Unknown mode"
    };

    static void Main() {
        System.Console.WriteLine(GetMessage(Mode.Manual, Status.Off));
    }
}

A Auto mode ON

B Manual mode ON

C Manual mode OFF

D Unknown mode

💡 Hint

Look at the nested switch for Mode.Manual and Status.Off.

For Mode.Manual and Status.Off, the nested switch returns "Manual mode OFF".

🧠 Conceptual

expert

Exhaustiveness in enum switch expressions

Which statement about C# switch expressions with enums is TRUE?

A You can only use switch statements, not switch expressions, with enums in C#.

B Switch expressions on enums always compile even if some enum values are missing cases.

C Switch expressions on enums do not support pattern matching.

D A switch expression on an enum must include a default case or cover all enum values to compile.

💡 Hint

Think about compiler checks for switch expressions on enums.

C# requires switch expressions on enums to be exhaustive by covering all enum values or having a default case.