Add lab6

lab/lab6/Question5/ManyShapes.java

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+/*
+ * Author: CHEN Yongyuan (Walter) 1930006025 from OOP(1007)
+ * Date: 2022/03/27
+ * Description: This is the class for the many shapes.
+ */
+
+import java.util.ArrayList;
+
+public class ManyShapes {
+	private ArrayList<Shape> allShapes;
+
+	/**
+	 * Constructor
+	 */
+	public ManyShapes() {
+		this.allShapes = new ArrayList<Shape>();
+	}
+
+	/**
+	 * addShape method takes a shape as argument and adds it to the arraylist.
+	 *
+	 * @param s the shape to be added
+	 */
+	public void addShape(Shape s) {
+		this.allShapes.add(s);
+	}
+
+	/**
+	 * listAllShapes methods prints on the screen the area of each shape in the
+	 * arraylist, one by one, using a loop. For example, if the arraylist currently
+	 * contains a Square object of size 5 and a Dot object the the listAllShapes
+	 * methods should print:
+	 *
+	 * Shape has area 25.0
+	 *
+	 * Shape has area 0.0
+	 */
+	public void listAllShapes() {
+		for (Shape s : this.allShapes) {
+			System.out.println("Shape has area " + s.area());
+		}
+	}
+
+	/**
+	 * Test.
+	 */
+	public static void testManyShapes() {
+		ManyShapes m = new ManyShapes();
+		m.addShape(new Circle(1.2, 3.4, 4.0)); // Upcast from Circle to Shape.
+		m.addShape(new Dot(1.2, 3.4)); // Upcast from Dot to Shape.
+		m.addShape(new Rectangle(1.2, 3.4, 4.0, 5.0)); // Upcast from Rectangle to Shape.
+		m.addShape(new Shape(1.2, 3.4));
+		m.addShape(new Square(1.2, 3.4, 5.0)); // Upcast from Square to Shape.
+		m.listAllShapes();
+	}
+}