Interface declaration syntax in C Sharp (C#) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare an interface named IAnimal.

C Sharp (C#)

public [1] IAnimal
{
    void Speak();
}

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

Ainterface

Bclass

Cstruct

Denum

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'class' instead of 'interface' keyword.

Trying to use 'struct' or 'enum' which are different types.

The keyword interface is used to declare an interface in C#.

2fill in blank

medium

Complete the code to declare an interface method named Move that returns void.

C Sharp (C#)

public interface IVehicle
{
    [1] Move();
}

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

Aint

Bbool

Cstring

Dvoid

Attempts:

3 left

💡 Hint

Common Mistakes

Using a return type like int or string when the method should return nothing.

Omitting the return type entirely.

Interface methods specify the return type. Here, void means no value is returned.

3fill in blank

hard

Fix the error in the interface declaration by completing the code.

C Sharp (C#)

public [1] IShape
{
    double GetArea();
}

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

Ainterface

Bstruct

Cnamespace

Dclass

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'class' instead of 'interface'.

Using unrelated keywords like 'namespace' or 'struct'.

The correct keyword to declare an interface is interface. Using 'class' or others causes errors.

4fill in blank

hard

Fill both blanks to declare an interface ICalculator with a method Add that returns an int.

C Sharp (C#)

public [1] ICalculator
{
    [2] Add(int a, int b);
}

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

Ainterface

Bvoid

Cint

Dclass

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'class' instead of 'interface'.

Using 'void' as return type when the method should return int.

The interface is declared with interface keyword and the method returns an int.

5fill in blank

hard

Fill all three blanks to declare an interface IPrinter with a method Print that takes a string and returns void.

C Sharp (C#)

public [1] IPrinter
{
    [2] Print([3] message);
}

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

Ainterface

Bvoid

Cstring

Dclass

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'class' instead of 'interface'.

Using wrong return type or parameter type.

The interface uses interface keyword, the method returns void, and the parameter type is string.