Pattern matching in switch in C Sharp (C#) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to match the integer 5 in the switch expression.

C Sharp (C#)

int number = 5;
switch (number)
{
    case [1]:
        Console.WriteLine("Number is five");
        break;
    default:
        Console.WriteLine("Number is not five");
        break;
}

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Aint

B"5"

Cnumber

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Using a string "5" instead of the integer 5.

Using the variable name instead of a constant value.

The case label must be the integer 5 to match the value of number.

2fill in blank

medium

Complete the code to use pattern matching to check if the object is a string.

C Sharp (C#)

object obj = "hello";
switch (obj)
{
    case [1] s:
        Console.WriteLine($"String with length {s.Length}");
        break;
    default:
        Console.WriteLine("Not a string");
        break;
}

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Astring

Bint

Cbool

Ddouble

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong type like int or bool.

Forgetting to include the variable name after the type.

The pattern string s matches if obj is a string and assigns it to s.

3fill in blank

hard

Fix the error in the switch expression to correctly match a nullable int with value 10.

C Sharp (C#)

int? number = 10;
switch (number)
{
    case [1]:
        Console.WriteLine("Number is ten");
        break;
    default:
        Console.WriteLine("Number is not ten");
        break;
}

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Aint n when n == 10

B10

Cint? n when n == 10

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Using just 10 without a pattern.

Using int? n which matches nullable but cannot use when condition properly.

The pattern int n when n == 10 matches a non-null int with value 10 inside the nullable.

4fill in blank

hard

Fill both blanks to create a switch expression that returns a description for the shape object.

C Sharp (C#)

object shape = new Circle();
string description = shape switch
{
    [1] => "It's a circle",
    [2] => "It's a square",
    _ => "Unknown shape"
};

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ACircle c

BSquare s

CTriangle t

DRectangle r

Attempts:

3 left

💡 Hint

Common Mistakes

Using types that don't match the shape object.

Omitting the variable name after the type.

The patterns Circle c and Square s match objects of those types.

5fill in blank

hard

Fill all three blanks to create a switch expression that returns a message based on the input object type and value.

C Sharp (C#)

object input = 42;
string message = input switch
{
    [1] when [2] > 40 => "Large integer",
    [3] => "Not a large integer",
    _ => "Unknown"
};

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Aint n

Bn

Cstring s

Ddouble d

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable name in the when condition that is not declared in the pattern.

Using the wrong type patterns.

The first pattern matches an int and uses n in the condition. The second pattern matches a string.