Switch expressions with patterns in C Sharp (C#) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to return the correct string for the number using a switch expression.

C Sharp (C#)

string result = number switch [1];

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A< 1 => "One", 2 => "Two", _ => "Other" >

B( 1 => "One", 2 => "Two", _ => "Other" )

C[ 1 => "One", 2 => "Two", _ => "Other" ]

D{ 1 => "One", 2 => "Two", _ => "Other" }

Attempts:

3 left

💡 Hint

Common Mistakes

Using parentheses or brackets instead of curly braces for switch expression.

Forgetting the underscore (_) as the default case.

The switch expression in C# uses curly braces with pattern cases inside.

2fill in blank

medium

Complete the switch expression to return "Positive" for numbers greater than zero.

C Sharp (C#)

string result = number switch {
    > 0 => "Positive",
    0 => "Zero",
    [1] => "Negative"
};

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A< 0

B> 0

C== 0

D>= 0

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>= 0' which overlaps with zero and positive cases.

Using '== 0' which duplicates the zero case.

The pattern '< 0' matches negative numbers in the switch expression.

3fill in blank

hard

Fix the error in the switch expression to correctly handle strings starting with 'A'.

C Sharp (C#)

string result = input switch {
    [1] => "Starts with A",
    _ => "Other"
};

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Astring s => s.StartsWith("A")

Bstring s when s.StartsWith("A")

Cstring s if s.StartsWith("A")

Dstring s where s.StartsWith("A")

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=>' instead of 'when' for conditions.

Using 'if' or 'where' which are invalid in this context.

The correct syntax for pattern matching with a condition is 'type variable when condition'.

4fill in blank

hard

Fill both blanks to return the correct description for the shape using switch expression with type patterns.

C Sharp (C#)

string description = shape switch {
    [1] => "Circle with radius " + c.Radius,
    [2] => "Rectangle with width " + r.Width + " and height " + r.Height,
    _ => "Unknown shape"
};

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ACircle c

BRectangle c

CRectangle r

DCircle r

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing variable names and types incorrectly.

Using the wrong variable name for the shape type.

Use type patterns with variable names matching the properties used in the expressions.

5fill in blank

hard

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

C Sharp (C#)

string message = obj switch {
    [1] when i > 0 => "Positive integer",
    [2] when s.Length == 0 => "Empty string",
    [3] => "Other"
};

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Aint i

Bstring s

C_

Ddouble d

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names or types in patterns.

Not using '_' for the default case.

Use type patterns with variable names for conditions and '_' as the default case.