Switch expression (modern C#) - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of a simple switch expression

What is the output of this C# code using a switch expression?

C Sharp (C#)

string GetDayType(int day) => day switch
{
    1 => "Monday",
    2 => "Tuesday",
    3 => "Wednesday",
    _ => "Other"
};

Console.WriteLine(GetDayType(2));

A Monday

B Other

C Tuesday

D Wednesday

💡 Hint

Look at the input value and match it with the switch cases.

The input is 2, which matches the case '2' returning "Tuesday".

❓ Predict Output

intermediate

Switch expression with property pattern

What will this code print?

C Sharp (C#)

record Person(string Name, int Age);

string Describe(Person p) => p switch
{
    { Age: < 18 } => "Child",
    { Age: >= 18 and < 65 } => "Adult",
    { Age: >= 65 } => "Senior",
    _ => "Unknown"
};

Console.WriteLine(Describe(new Person("Alice", 70)));

A Senior

B Adult

C Child

D Unknown

💡 Hint

Check the age property and the conditions in the switch.

Age 70 matches the pattern { Age: >= 65 }, so it returns "Senior".

❓ Predict Output

advanced

Switch expression with tuple patterns

What is the output of this code?

C Sharp (C#)

string GetResult(int x, int y) => (x, y) switch
{
    (0, 0) => "Origin",
    (_, 0) => "X-axis",
    (0, _) => "Y-axis",
    _ => "Plane"
};

Console.WriteLine(GetResult(0, 5));

A Y-axis

B X-axis

C Origin

D Plane

💡 Hint

Look at the tuple values and which pattern matches first.

The tuple (0,5) matches the pattern (0, _) which returns "Y-axis".

❓ Predict Output

advanced

Switch expression with when clause

What will this code print?

C Sharp (C#)

int Grade(int score) => score switch
{
    var s when s >= 90 => 4,
    var s when s >= 80 => 3,
    var s when s >= 70 => 2,
    var s when s >= 60 => 1,
    _ => 0
};

Console.WriteLine(Grade(85));

A 4

B 3

C 2

D 1

💡 Hint

Check which condition the score 85 satisfies first.

85 is >= 80 but less than 90, so it returns 3.

🧠 Conceptual

expert

Behavior of switch expression with null input

Consider this switch expression: string DescribeInput(string? input) => input switch { null => "No input", "" => "Empty string", _ => "Has value" }; What is the output of DescribeInput(null)?

A "Has value"

B Throws NullReferenceException

C "Empty string"

D "No input"

💡 Hint

Check how null is matched in the switch expression.

The input is null, so it matches the first case returning "No input".