Why generics are needed in C Sharp (C#) - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a list that can store integers.

C Sharp (C#)

List<[1]> numbers = new List<[1]>();

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Aint

Bstring

Cdouble

Dbool

Attempts:

3 left

💡 Hint

Common Mistakes

Using string instead of int for numbers.

Forgetting to specify the type inside the angle brackets.

We use int to create a list that stores integers.

2fill in blank

medium

Complete the code to create a generic method that returns the default value of any type.

C Sharp (C#)

public [1] GetDefaultValue<T>() { return default(T); }

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Aobject

Bvoid

Cint

DT

Attempts:

3 left

💡 Hint

Common Mistakes

Using void as return type when the method returns a value.

Using a specific type like int instead of the generic type.

The method returns a value of type T, so the return type must be T.

3fill in blank

hard

Fix the error in the generic class declaration.

C Sharp (C#)

public class Box<[1]> { public T Value; }

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Avar

BType

CT

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Using a keyword like var as a type parameter.

Using a lowercase name that does not match the usage.

The generic type parameter must be declared as T to match the usage inside the class.

4fill in blank

hard

Fill both blanks to create a generic method that swaps two variables.

C Sharp (C#)

public void Swap<[1]>(ref [2] a, ref [2] b) { [2] temp = a; a = b; b = temp; }

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AT

Bint

Dstring

Attempts:

3 left

💡 Hint

Common Mistakes

Using different types for the type parameter and variables.

Using a specific type like int instead of the generic type.

The generic type parameter is T, and the variables use type T to swap any type.

5fill in blank

hard

Fill all three blanks to create a generic dictionary comprehension that filters entries with values greater than zero.

C Sharp (C#)

var filtered = [1].Where(kv => kv.Value [2] 0).ToDictionary(kv => kv.[3], kv => kv.Value);

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Adata

B>

CKey

Ditems

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong collection name.

Using the wrong comparison operator.

Accessing the key incorrectly.

We filter the dictionary data for values greater than zero and create a new dictionary using the keys.