Learn Challenge: Encapsulation

The base code has two classes called Vehicle and Car. Some of the fields need to be hidden while some need to be exposed.

Adjust the visibility of the type and modelYear fields in Vehicle such that they are not accessible from outside the class, including derived classes;
Create a new method called getModelYear inside the Vehicle class such that it returns the modelYear. This method should be accessible from anywhere. This method will allow the users of this class to access the modelYear but not be able to modify it from outside;
The ownerName and fuel properties should not be accessible from anywhere;
Make a method called getFuel which returns the value of fuel;
Make a method called addFuel which takes in a float argument called fuel. Inside the method, add the value of fuel to the property fuel (this.fuel).

index.cs


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using System;

class Vehicle
{
    // Edit code below this line
    public string type;
    public int modelYear;
    // Edit code above this line

    // Create a method below this line

    // Create a method above this line

    public Vehicle(string type, int modelYear)
    {
        this.type = type;
        this.modelYear = modelYear;
    }
}

class Car : Vehicle
{
    // Edit code below this line
    public string brandName;
    public string numberPlate;
    public string ownerName;
    public float fuel;
    // Edit code above this line

    // Create a method below this line

    // Create a method above this line

    public Car(int modelYear, string brandName, string numberPlate, string ownerName, float fuel) : base("Car", modelYear)
    {
        this.brandName = brandName;
        this.numberPlate = numberPlate;
        this.ownerName = ownerName;
        this.fuel = fuel;
    }
}

class Program
{
    static void Main()
    {
        // Create an instance of Car
        Car myCar = new Car(2022, "Toyota", "ABC123", "John Doe", 50.0f);

        // Accessing properties and methods from Car class
        Console.WriteLine($"Brand: {myCar.brandName}");
        Console.WriteLine($"Number Plate: {myCar.numberPlate}");

        // Accessing getModelYear method from Vehicle class
        Console.WriteLine($"Model Year: {myCar.getModelYear()}");

        // Accessing getFuel method from Car class
        Console.WriteLine($"Fuel: {myCar.getFuel()}");

        // Adding fuel using addFuel method
        myCar.addFuel(10.0f);
        Console.WriteLine($"After adding fuel, new Fuel: {myCar.getFuel()}");
    }
}

The methods getModelYear and getFuel are getter methods. They take no arguments, are public, and only return a value.
The method addFuel is a setter method. It is public and takes one float argument called fuel. For updating the value of the fuel you might need to use this keyword. (this.fuel += fuel)

index.cs


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using System;

class Vehicle
{
    // Edit code below this line
    private string type;
    private int modelYear;
    // Edit code above this line

    // Create a method below this line
    public int getModelYear()
    {
        return modelYear;
    }
    // Create a method above this line

    public Vehicle(string type, int modelYear)
    {
        this.type = type;
        this.modelYear = modelYear;
    }
}

class Car : Vehicle
{
    // Edit code below this line
    public string brandName;
    public string numberPlate;
    private string ownerName;
    private float fuel;
    // Edit code above this line

    // Create a method below this line
    public float getFuel()
    {
        return fuel;
    }

    public void addFuel(float fuel)
    {
        this.fuel += fuel;
    }
    // Create a method above this line

    public Car(int modelYear, string brandName, string numberPlate, string ownerName, float fuel) 
        : base("Car", modelYear)
    {
        this.brandName = brandName;
        this.numberPlate = numberPlate;
        this.ownerName = ownerName;
        this.fuel = fuel;
    }
}

class Program
{
    static void Main()
    {
        // Create an instance of Car
        Car myCar = new Car(2022, "Toyota", "ABC123", "John Doe", 50.0f);

        // Accessing properties and methods from Car class
        Console.WriteLine($"Brand: {myCar.brandName}");
        Console.WriteLine($"Number Plate: {myCar.numberPlate}");

        // Accessing getModelYear method from Vehicle class
        Console.WriteLine($"Model Year: {myCar.getModelYear()}");

        // Accessing getFuel method from Car class
        Console.WriteLine($"Fuel: {myCar.getFuel()}");

        // Adding fuel using addFuel method
        myCar.addFuel(10.0f);
        Console.WriteLine($"After adding fuel, new Fuel: {myCar.getFuel()}");
    }
}

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Section 5. Chapter 7

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The base code has two classes called Vehicle and Car. Some of the fields need to be hidden while some need to be exposed.

Adjust the visibility of the type and modelYear fields in Vehicle such that they are not accessible from outside the class, including derived classes;
Create a new method called getModelYear inside the Vehicle class such that it returns the modelYear. This method should be accessible from anywhere. This method will allow the users of this class to access the modelYear but not be able to modify it from outside;
The ownerName and fuel properties should not be accessible from anywhere;
Make a method called getFuel which returns the value of fuel;
Make a method called addFuel which takes in a float argument called fuel. Inside the method, add the value of fuel to the property fuel (this.fuel).

index.cs


              12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364
            
using System;

class Vehicle
{
    // Edit code below this line
    public string type;
    public int modelYear;
    // Edit code above this line

    // Create a method below this line

    // Create a method above this line

    public Vehicle(string type, int modelYear)
    {
        this.type = type;
        this.modelYear = modelYear;
    }
}

class Car : Vehicle
{
    // Edit code below this line
    public string brandName;
    public string numberPlate;
    public string ownerName;
    public float fuel;
    // Edit code above this line

    // Create a method below this line

    // Create a method above this line

    public Car(int modelYear, string brandName, string numberPlate, string ownerName, float fuel) : base("Car", modelYear)
    {
        this.brandName = brandName;
        this.numberPlate = numberPlate;
        this.ownerName = ownerName;
        this.fuel = fuel;
    }
}

class Program
{
    static void Main()
    {
        // Create an instance of Car
        Car myCar = new Car(2022, "Toyota", "ABC123", "John Doe", 50.0f);

        // Accessing properties and methods from Car class
        Console.WriteLine($"Brand: {myCar.brandName}");
        Console.WriteLine($"Number Plate: {myCar.numberPlate}");

        // Accessing getModelYear method from Vehicle class
        Console.WriteLine($"Model Year: {myCar.getModelYear()}");

        // Accessing getFuel method from Car class
        Console.WriteLine($"Fuel: {myCar.getFuel()}");

        // Adding fuel using addFuel method
        myCar.addFuel(10.0f);
        Console.WriteLine($"After adding fuel, new Fuel: {myCar.getFuel()}");
    }
}

The methods getModelYear and getFuel are getter methods. They take no arguments, are public, and only return a value.
The method addFuel is a setter method. It is public and takes one float argument called fuel. For updating the value of the fuel you might need to use this keyword. (this.fuel += fuel)

index.cs


              12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576
            
using System;

class Vehicle
{
    // Edit code below this line
    private string type;
    private int modelYear;
    // Edit code above this line

    // Create a method below this line
    public int getModelYear()
    {
        return modelYear;
    }
    // Create a method above this line

    public Vehicle(string type, int modelYear)
    {
        this.type = type;
        this.modelYear = modelYear;
    }
}

class Car : Vehicle
{
    // Edit code below this line
    public string brandName;
    public string numberPlate;
    private string ownerName;
    private float fuel;
    // Edit code above this line

    // Create a method below this line
    public float getFuel()
    {
        return fuel;
    }

    public void addFuel(float fuel)
    {
        this.fuel += fuel;
    }
    // Create a method above this line

    public Car(int modelYear, string brandName, string numberPlate, string ownerName, float fuel) 
        : base("Car", modelYear)
    {
        this.brandName = brandName;
        this.numberPlate = numberPlate;
        this.ownerName = ownerName;
        this.fuel = fuel;
    }
}

class Program
{
    static void Main()
    {
        // Create an instance of Car
        Car myCar = new Car(2022, "Toyota", "ABC123", "John Doe", 50.0f);

        // Accessing properties and methods from Car class
        Console.WriteLine($"Brand: {myCar.brandName}");
        Console.WriteLine($"Number Plate: {myCar.numberPlate}");

        // Accessing getModelYear method from Vehicle class
        Console.WriteLine($"Model Year: {myCar.getModelYear()}");

        // Accessing getFuel method from Car class
        Console.WriteLine($"Fuel: {myCar.getFuel()}");

        // Adding fuel using addFuel method
        myCar.addFuel(10.0f);
        Console.WriteLine($"After adding fuel, new Fuel: {myCar.getFuel()}");
    }
}

Everything was clear?

Thanks for your feedback!

Section 5. Chapter 7