update,

_resources/it114105/itp4510/Lab01/Lab1.2/q3/Circle.java

@@ -0,0 +1,34 @@
+public class Circle extends Shape{
+    private double radius;
+    private Point center;
+
+    public Circle(double radius, double x, double y){
+        super("circle");
+        this.radius = radius;
+        center = new Point(x, y);
+    }
+
+    public double getRadius(){
+        return radius;
+    }
+
+    public Point getCenter(){
+        return center;
+    }
+
+    public void setRadius(double radius){
+        this.radius = radius;
+    }
+
+    public void setCenter(Point center){
+        this.center = center;
+    }
+
+    public double getArea(){
+        return radius*radius*3.1416;
+    }
+
+    public String toString(){
+        return "center=" + center.toString() + "; radius=" + radius;
+    }
+}

_resources/it114105/itp4510/Lab01/Lab1.2/q3/Point.java

@@ -0,0 +1,24 @@
+public class Point {
+    private double x, y;
+
+    public Point(double a, double b) {
+        setPoint(a, b);
+    }
+
+    public void setPoint(double a, double b) {
+        x = a;
+        y = b;
+    }
+
+    public double getX() {
+        return x;
+    }
+
+    public double getY() {
+        return y;
+    }
+
+    public String toString() {
+        return "[" + x + ", " + y + "]";
+    }
+}

_resources/it114105/itp4510/Lab01/Lab1.2/q3/Rectangle.java

@@ -0,0 +1,40 @@
+public class Rectangle extends Shape{
+    private Point topLeft;
+    private double width;
+    private double height;
+
+    public Rectangle(double width, double height, double x, double y) {
+        super("rectangle");
+        topLeft = new Point(x, y);
+        this.width = width;
+        this.height = height;
+    }
+
+    public double getWidth() {
+        return width;
+    }
+
+    public double getHeight() {
+        return height;
+    }
+
+    public Point getTopLeft() {
+        return topLeft;
+    }
+
+    public void setWidth(double width) {
+        this.width = width;
+    }
+
+    public void setHeight(double height) {
+        this.height = height;
+    }
+
+    public double getArea() {
+        return width * height;
+    }
+
+    public String toString() {
+        return "top left=" + topLeft.toString() + "; width=" + width + "; height=" + height;
+    }
+}

_resources/it114105/itp4510/Lab01/Lab1.2/q3/Shape.java

@@ -0,0 +1,13 @@
+public abstract class Shape {
+    protected String name;
+
+    public Shape(String n) {
+        name = n;
+    }
+
+    public abstract double getArea();
+
+    public String getName() {
+        return name;
+    }
+}

_resources/it114105/itp4510/Lab01/Lab1.2/q3/TestShape.java

@@ -0,0 +1,12 @@
+public class TestShape {
+    public static void main(String[] args) {
+        Shape[] myShapes = new Shape[3];
+        myShapes[0] = new Circle(10.5, 20, 25);
+        myShapes[1] = new Rectangle(30.5, 23.5, 15.5, 20.5);
+        myShapes[2] = new Circle(8, 9.5, 10.5);
+        for (int i = 0; i < myShapes.length; i++) {
+            System.out
+                    .println(myShapes[i].getName() + "=" + myShapes[i].toString() + "; Area=" + myShapes[i].getArea());
+        }
+    }
+}