lab8 finished

lab/lab8/Question5/Rectangle.java

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+/*
+ * Author: CHEN Yongyuan (Walter) 1930006025 from OOP(1007)
+ * Date: 2022-04-14
+ * Description: Rectangle class inherited from Shape class
+ */
+
+public class Rectangle extends Shape {
+	private double width;
+	private double length;
+
+	/**
+	 * Constructor
+	 * 
+	 * @param x      x coordinate of the center of the rectangle
+	 * @param y      y coordinate of the center of the rectangle
+	 * @param width  width of the rectangle
+	 * @param length length of the rectangle
+	 */
+	public Rectangle(double x, double y, double width, double length) {
+		super(x, y);
+		this.width = width;
+		this.length = length;
+	}
+
+	/**
+	 * Calculates the area of the rectangle.
+	 *
+	 * @return the area of the rectangle
+	 */
+	@Override
+	public double area() {
+		return width * length;
+	}
+
+	/**
+	 * Resizing a rectangle changes its width and length to both be newSize.
+	 *
+	 * @param newSize the new size of the rectangle
+	 */
+	@Override
+	public void resize(double newSize) {
+		width = newSize;
+		length = newSize;
+	}
+
+	/**
+	 * Test.
+	 */
+	public static void testRectangle() {
+		Rectangle r = new Rectangle(1.2, 3.4, 4.0, 5.0);
+		// getX, getY, and move are inherited from Shape.
+		// area and resize come from Rectangle itself.
+		System.out.println(r.getX() == 1.2);
+		System.out.println(r.getY() == 3.4);
+		System.out.println(r.area() == 20.0);
+		// Move the rectangle. The area does not change.
+		r.move(7.8, 9.0);
+		System.out.println(r.getX() == 9.0);
+		System.out.println(r.getY() == 12.4);
+		System.out.println(r.area() == 20.0);
+		// Resize the rectangle. The area changes but not the position.
+		r.resize(12.0);
+		System.out.println(r.getX() == 9.0);
+		System.out.println(r.getY() == 12.4);
+		System.out.println(r.area() == 144.0);
+	}
+}