Course of Raku / Objects, I/O, and exceptions / Classes and objects / Methods / Exercises / Rectangle area

Solution: Rectangle area

Here is a possible solution to the task.

Code

class Rectangle {
    has $.width;
    has $.height;

    method area {
        $.width * $.height;
    }

    method describe {
        "area is " ~ self.area;
    }
}

say Rectangle.new(width => 3, height => 4).describe;

🦋 You can find the source code in the file rectangle-area.raku.

Output

area is 12

Comments

The area method reads the object’s own width and height through their accessors and multiplies them — for a 3 by 4 rectangle, that is 12.
The describe method does not repeat that calculation. Instead it calls self.area, running the area method on the same object and reusing its result. Building larger behaviour out of smaller methods this way keeps each method responsible for one job.

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