Lab: Instance Method Overloading

Objective

In this lab, we will delve into the concept of instance method overloading by applying it to a practical example. We’ll refine and expand a given class by adding overloadeds of an existing instance method. The purpose is to understand how to implement method overloading to enhance code readability and maintainability.

Provided Code

Carefully review the provided code. Notice the structure of the Rectangle class, which includes private fields for dimensions, a constructor to initialize these fields, and a Scale method designed to adjust the rectangle’s size. The Scale method double to scale both dimensions equally, while the second takes two doubles to scale each dimension independently.

class Rectangle
{
    private double width, height;

    public Rectangle(double width, double height)
    {
        this.width = width;
        this.height = height;
    }

    public void Scale(double widthFactor, double heightFactor)
    {
        width *= widthFactor;
        height *= heightFactor;
    }

    public void Print()
    {
        Console.WriteLine($"({width} x {height})");
    }
}

The below script needs to be able to find the current output cell; this is an easy method to get it.

Rectangle rect = new Rectangle(20, 10);
rect.Print();

rect.Scale(3, 2);
rect.Print();

(20 x 10)

(60 x 20)

Instructions

We will now enhance our Rectangle class by adding more overloaded methods and utilizing them.

Step 1: Add Overloaded Scale method

Create a new overloaded Scale method that accepts a single double parameter. This method should call the other Scale method and thereby scale the rectangle with the same factor in both dimensions.

Instantiate a Rectangle and use both Scale methods to demonstrate their functionality. Print the dimensions after each scaling operation to verify the methods work as expected.

Rectangle rect = new Rectangle(200, 100);
rect.Print();

rect.Scale(0.5);
rect.Print();

rect.Scale(2, 1);
rect.Print();

(200 x 100)

(100 x 50)

(200 x 50)

Step 2: Add an Overload That Takes a Point

Consider the following class that can be used to represents points:

class Point
{
    public int X;
    public int Y;

    public Point(int x, int y)
    {
        X = x;
        Y = y;
    }
}

Add the class to your code base and add another overload of the method Scale with the signature void Scale(Point point).

Go back to the main method and use all three overloads of Scale to make sure that they all work.

Rectangle rect = new Rectangle(2, 1);
rect.Print();

Point point = new Point(10, 5);
rect.Scale(point);
rect.Print();

rect.Scale(new Point(2, 1));
rect.Print();

rect.Scale(0.5);
rect.Print();

rect.Scale(10, 100);
rect.Print();

(2 x 1)

(20 x 5)

(40 x 5)

(20 x 2.5)

(200 x 250)

Challenge

Add three instance methods with the following signatures:

public void SetAspectRatio (double ratio);
public void SetAspectRatio (Rectangle other);
public void SetAspectRatio (Point point);

These methods should change the dimensions of a Rectangle object in order to achieve the desired aspect ratio (in terms of width/height).

There’s many ways to choose whether to change the width or the height but let’s here choose a strategy where we always increase a dimension. To determine which dimension needs to be increased we can check whether the new ratio is larger than the old ratio. If the new ratio is larger then we should increase width, and if not then we should increase height.

When you’re done you should be able to do the following:

Rectangle rect = new Rectangle(5, 20);
rect.Print();

rect.SetAspectRatio(0.5);
rect.Print();

rect.SetAspectRatio(new Rectangle(16, 9));
rect.Print();

rect.SetAspectRatio(new Point(9, 16));
rect.Print();

(5 x 20)

(10 x 20)

(35.55555555555556 x 20)

(35.55555555555556 x 63.20987654320988)

Conclusion

Good job. You’re on fire. 🔥