Object Shape Rectangle Ellipse Triangle Circle Object Shape

ΠΑΡΑΔΕΙΓΜΑ Object Shape Rectangle Ellipse Βασική κλάση Triangle Circle Object Shape Rectangle Ellipse Triangle Circle

ΠΑΡΑΔΕΙΓΜΑ public class Circle { protected double x, y, r ; public Circle (double x, double y, double r) {this. x=x; this. y=y; this. r = r ; } public double area ( ) {return 3. 1416*r*r ; } } public class Graphic. Circle extends Circle{ Color outline, fill ; public void draw ( ) { … } }

ΠΑΡΑΔΕΙΓΜΑ Circle x, y, r area() Graphic. Circle outline, fill draw()

ΠΑΡΑΔΕΙΓΜΑ abstract class Shape {} class Rectangle extends Shape {} class Ellipse extends Shape {} class Triangle extends Shape {} class Circle extends Ellipse {} abstract class Shape { public abstract double area(); public abstract double circumference(); }

ΚΛΗΡΟΝΟΜΙΚΟΤΗΤΑ ΚΑΙ ΔΗΜΙΟΥΡΓΟΙ public class Graphic. Circle extends Circle{ Color outline, fill ; public Graphic. Circle (double x, double y, double r, Color outline, Color fill) { this. x = x; this. y=y; this. r=r; this. outline=outline; this. fill=fill; } public class Graphic. Circle extends Circle{ Color outline, fill ; public Graphic. Circle (double x, double y, double r, Color outline, Color fill) { super(x, y, r); this. outline=outline; this. fill=fill; }

ΠΑΡΑΔΕΙΓΜΑ class Parent{ public Parent () { System. out. println (“Hello Parent”); }} class Child extends Parent { String message = “No Child”; public Child (String message) { this. message = message; System. out. println (message); }} Τι αποτέλεσμα θα έχει η Child c = new Child(“First Child”); 1. Εκτύπωση: Hello Parent (λόγω έμμεσου super(); ) 2. Ανάθεση: “First Child” στην message του c (λόγω ) 3. Εκτύπωση: First Child (λόγω )

ΑΝΑΖΗΤΗΣΗ ΤΙΜΗΣ ΜΕΤΑΒΛΗΤΗΣ class A size = 4 class B size = 3 sizec 1 = 7 set. Size 1 (x) {size = x; } class C size = 2 set. Size 2 (x) {size = x; } C (size) {this. size = size; } c 1 size = 5 size = 6 c 2 C c 1 = new C(5); C c 2 = new C(); System. out. println (c 1. size); 5 System. out. println (c 2. size); 2 c 1. set. Size 2(6); c 1. set. Size 1(7); System. out. println (c 1. size); 6

ΑΝΑΖΗΤΗΣΗ ΤΙΜΗΣ ΜΕΤΑΒΛΗΤΗΣ class A size = 4 Μέσα σε μέθοδο της C class B size = 3 set. Size 1 (x) {size = x; } class C size = 2 set. Size 2 (x) {size = x; } C (size) {this. size = size; } c 1 size = 5 c 2 super. set. Size 1(8) B super. size ((B) this). size B B (ισοδύναμες εκφράσεις) ((A) this). size A ((B) this). set. Size 1(8)