Base keyword behavior in C Sharp (C#) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to call the base class method from the derived class.

C Sharp (C#)

public class Animal {
    public virtual string Speak() {
        return "Animal sound";
    }
}

public class Dog : Animal {
    public override string Speak() {
        return [1].Speak();
    }
}

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

Abase

Bthis

Csuper

Dparent

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'this' instead of 'base' to call the base class method.

Using 'super' which is not a C# keyword.

The 'base' keyword in C# is used to access members of the base class from a derived class.

2fill in blank

medium

Complete the constructor to call the base class constructor with a parameter.

C Sharp (C#)

public class Vehicle {
    public string Brand;
    public Vehicle(string brand) {
        Brand = brand;
    }
}

public class Car : Vehicle {
    public Car(string brand) : [1](brand) {
    }
}

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

Athis

Bbase

Csuper

Dparent

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'this' instead of 'base' to call the base constructor.

Using 'super' which is not valid in C#.

In C#, the 'base' keyword is used to call the base class constructor from a derived class constructor.

3fill in blank

hard

Fix the error by correctly calling the base class method inside the overridden method.

C Sharp (C#)

public class Printer {
    public virtual void Print() {
        Console.WriteLine("Printing from Printer");
    }
}

public class ColorPrinter : Printer {
    public override void Print() {
        [1].Print();
        Console.WriteLine("Printing in color");
    }
}

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

Abase

Bthis

Csuper

Dparent

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'this' which calls the current class method causing recursion.

Using 'super' which is not a C# keyword.

The 'base' keyword is used to call the base class method from an overridden method in C#.

4fill in blank

hard

Fill both blanks to correctly override a method and call the base method inside it.

C Sharp (C#)

public class Logger {
    public virtual void Log(string message) {
        Console.WriteLine("Log: " + message);
    }
}

public class FileLogger : Logger {
    public override void Log(string message) {
        [1].Log(message);
        Console.WriteLine("Writing to file");
    }
}

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

Abase

Bthis

Csuper

Dparent

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'super' or 'parent' which are invalid in C#.

Using 'this' to call the base method causing recursion.

Use 'base' to call the base class method and 'this' to refer to the current instance if needed.

5fill in blank

hard

Fill all three blanks to override a method, call the base method, and add extra behavior.

C Sharp (C#)

public class Shape {
    public virtual double Area() {
        return 0;
    }
}

public class Circle : Shape {
    private double radius;
    public Circle(double radius) {
        this.radius = radius;
    }
    public override double Area() {
        double baseArea = [1].Area();
        double circleArea = Math.PI * radius * radius;
        return baseArea + [2];
    }
}

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

Athis

BcircleArea

Cbase

Dradius

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'this' instead of 'base' to call the base method.

Returning only circleArea without adding baseArea.

Use 'base' to call the base method, add 'circleArea' to it, and 'this' refers to the current instance.