Add lab6

lab/lab6/Question7/Rectangle.java

@@ -0,0 +1,52 @@
+/*
+ * Author: CHEN Yongyuan (Walter) 1930006025 from OOP(1007)
+ * Date: 2022/03/27
+ * Description: This is the Rectangle class.
+ */
+
+public class Rectangle extends Shape {
+	private double width;
+	private double height;
+
+	/**
+	 * Constructor
+	 * 
+	 * @param x      the x coordinate of the center of the rectangle
+	 * @param y      the y coordinate of the center of the rectangle
+	 * @param width  the width of the rectangle
+	 * @param length the length of the rectangle
+	 */
+	public Rectangle(double x, double y, double width, double length) {
+		super(x, y);
+		this.width = width;
+		this.height = length;
+	}
+
+	/**
+	 * Override the area method
+	 *
+	 * @return double
+	 */
+	@Override
+	public double area() {
+		return width * height;
+	}
+
+	/**
+	 * toString
+	 */
+	@Override
+	public String toString() {
+		return this.getClass().getName() + " has area " + area();
+	}
+
+	/**
+	 * Test
+	 */
+	public static void testRectangle() {
+		Rectangle r1 = new Rectangle(1.0, 2.0, 3.0, 4.0);
+		System.out.println(r1.getX() == 1.0);
+		System.out.println(r1.getY() == 2.0);
+		System.out.println(r1.area() == 12.0);
+	}
+}