public class Rectangle {
    int x, y;

    /* Create a new rectangle with the default size.
     * This is a constructor that takes no arguments.
     */
    public Rectangle() {
        x = 10;
        y = 10;
    }

    /* Create a new rectangle with the given size.
     * `this` keyword access the class's `x` and `y` specifically,
     * otherwise it would refer to the local ones.
     * This is also a constructor! It just takes more arguments.
     */
    public Rectangle(int x, int y) {
        this.x = x;
        this.y = y;
    }

    /* Works on any Rectangle class.
     * This is a method given to an object.
     * Example:
     * ```
     * Rectangle r = new Rectangle(10, 10);
     * int area = r.getArea();
     * System.out.println(area); // 100
     * ```
     */
    public int getArea() {
        return x * y;
    }
}