Constant patterns in C Sharp (C#) - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of constant pattern matching with int

What is the output of this C# code using constant pattern matching?

C Sharp (C#)

int number = 5;
string result = number switch
{
    1 => "One",
    5 => "Five",
    _ => "Other"
};
Console.WriteLine(result);

A One

B Compilation error

C Other

D Five

💡 Hint

Look at which constant matches the variable 'number'.

The switch expression matches the constant 5, so it returns "Five".

❓ Predict Output

intermediate

Constant pattern with string and null

What will this C# code print?

C Sharp (C#)

string? text = null;
string output = text switch
{
    null => "Null value",
    "hello" => "Greeting",
    _ => "Unknown"
};
Console.WriteLine(output);

A Greeting

B Null value

C Unknown

D Runtime exception

💡 Hint

Check how the null constant pattern works.

The variable 'text' is null, so the null pattern matches and returns "Null value".

❓ Predict Output

advanced

Pattern matching with multiple constant patterns

What is the output of this code snippet?

C Sharp (C#)

char letter = 'a';
string category = letter switch
{
    'a' or 'e' or 'i' or 'o' or 'u' => "Vowel",
    'y' => "Sometimes vowel",
    _ => "Consonant"
};
Console.WriteLine(category);

A Consonant

B Sometimes vowel

C Vowel

D Compilation error

💡 Hint

Check which constant pattern matches the letter 'a'.

The letter 'a' matches the first pattern with multiple constants, so it prints "Vowel".

❓ Predict Output

advanced

Constant pattern with nullable value types

What will this code print?

C Sharp (C#)

int? number = 0;
string result = number switch
{
    0 => "Zero",
    null => "No value",
    _ => "Other"
};
Console.WriteLine(result);

A Zero

B No value

C Other

D Runtime exception

💡 Hint

Remember how nullable types match constant patterns.

The nullable int has value 0, so it matches the constant 0 pattern and prints "Zero".

❓ Predict Output

expert

Constant pattern with enums and default case

Given this enum and code, what is the output?

C Sharp (C#)

enum Status { Ready, Running, Stopped }

Status current = Status.Running;
string message = current switch
{
    Status.Ready => "Ready to start",
    Status.Stopped => "Stopped",
    _ => "In progress"
};
Console.WriteLine(message);

A In progress

B Stopped

C Compilation error

D Ready to start

💡 Hint

Check which enum value matches the constant patterns.

The current status is Running, which matches the default case, so it prints "In progress".