Why polymorphism matters in C Sharp (C#) - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a base class named Animal.

C Sharp (C#)

public class [1] {
    public void Speak() {
        Console.WriteLine("Animal sound");
    }
}

Drag options to blanks, or click blank then click option'

AAnimal

BDog

CCat

DBird

Attempts:

3 left

💡 Hint

Common Mistakes

Using a specific animal name like Dog or Cat for the base class.

The base class should be named Animal to represent a general animal.

2fill in blank

medium

Complete the code to override the Speak method in the Dog class.

C Sharp (C#)

public class Dog : Animal {
    public override void [1]() {
        Console.WriteLine("Bark");
    }
}

Drag options to blanks, or click blank then click option'

ASpeak

BRun

CEat

DSleep

Attempts:

3 left

💡 Hint

Common Mistakes

Using a method name that does not exist in the base class.

The method Speak is overridden to provide a specific sound for Dog.

3fill in blank

hard

Fix the error in the code by completing the method declaration to allow polymorphism.

C Sharp (C#)

public class Animal {
    public [1] void Speak() {
        Console.WriteLine("Animal sound");
    }
}

Drag options to blanks, or click blank then click option'

Astatic

Babstract

Cvirtual

Dsealed

Attempts:

3 left

💡 Hint

Common Mistakes

Using static which prevents overriding.

Using sealed which prevents inheritance.

Using abstract without making the class abstract.

The virtual keyword allows derived classes to override the method, enabling polymorphism.

4fill in blank

hard

Fill both blanks to create a list of animals and call their Speak method polymorphically.

C Sharp (C#)

List<[1]> animals = new List<[2]> {
    new Dog(),
    new Cat()
};

foreach(var animal in animals) {
    animal.Speak();
}

Drag options to blanks, or click blank then click option'

AAnimal

BDog

CCat

Dobject

Attempts:

3 left

💡 Hint

Common Mistakes

Using a specific animal type like Dog or Cat for the list type.

The list should be of type Animal to hold different animal objects and call their overridden methods.

5fill in blank

hard

Fill all three blanks to implement polymorphism with an interface and classes.

C Sharp (C#)

public interface I[1] {
    void Speak();
}

public class [2] : I[1] {
    public void Speak() {
        Console.WriteLine("Meow");
    }
}

I[1] animal = new [2]();
animal.Speak();

Drag options to blanks, or click blank then click option'

AAnimal

BCat

CDog

DPet

Attempts:

3 left

💡 Hint

Common Mistakes

Mismatching interface and class names.

Not using the interface type for the variable.

The interface is named IAnimal, the class Cat implements it, and the variable uses the interface type to call Speak polymorphically.