1. Object-Oriented Programming
color
size
getColor
drift
draw
x, y

2. What is a Balloon?

3. What is a Balloon? It Depends...

4. What is a Balloon? It Depends...
Is it for a game app?
Is it for bookstore inventory app?

5. What is a Balloon? It Depends...
Is it for a game app? If so, a balloon has:
color
size
position on screen

6. What is a Balloon? It Depends...
Is it for a game app? If so, a balloon has:
color
size
position on screen
Is it for bookstore inventory app? If so, a balloon has:
price
manufacturer
shelf number

7. Description of a Balloon:
done
public class Balloon { }

8. Description of a Balloon:
(1) balloon’s features are:
color
size
position on screen
done
public class Balloon { }

9. Description of a Balloon:
(1) balloon’s features are:
color
size
position on screen
done
public class Balloon {
// data members
String color;
double size;
double x, y; }

10. Description of a Balloon:
(1) balloon’s features are:
color
size
position on screen
(3) balloon’s behaviors are:
report its features
drift
draw itself
done
public class Balloon {
// data members
String color;
double size;
double x, y; }

11. Description of a Balloon:
(1) balloon’s features are:
color
size
position on screen
(3) balloon’s behaviors are:
report its features
drift
draw itself
done
public class Balloon {
// data members
String color;
double size;
double x, y;
// methods
String getColor()
void drift( double dx, ... )
void draw() }

12. Description of a Balloon:
(1) balloon’s features are:
color
size
position on screen
(2) balloon’s can be created:
by giving values for features
(3) balloon’s behaviors are:
report its features
drift
draw itself
done
public class Balloon {
// data members
String color;
double size;
double x, y;
// methods
String getColor()
void drift( double dx, ... )
void draw() }

13. Description of a Balloon:
(1) balloon’s features are:
color
size
position on screen
(2) balloon’s can be created:
by giving values for features
(3) balloon’s behaviors are:
report its features
drift
draw itself
done
public class Balloon {
// data members
String color;
double size;
double x, y;
// constructor(s)
Balloon( String c, ..., ...)
// methods
String getColor()
void drift( double dx, ... )
void draw() }

14. public class Balloon {
// data members
private String color;
private double size;
private double x, y;
// constructor(s)
public Balloon( String c, ..., ...)
// methods
public String getColor()
public void drift( double dx, ... )
public void draw() }

15. public Balloon( String c, ..., ...) // methods
public class Balloon {
// data members
private String color;
private double size;
private double x, y;
// constructor(s)
public Balloon( String c, ..., ...)
// methods
public String getColor()
public void drift( double dx, ... )
public void draw() }
private means hidden
public means available

16. You – Designer of balloon
public class Balloon {
// data members
private String color;
private double size;
private double x, y;
// constructor(s)
public Balloon( String c, ..., ...)
// methods
public String getColor()
public void drift( double dx, ... )
public void draw() }
You – Designer of balloon
know everything
about the balloon

17. Balloon balloon = new Balloon( ... );
public class ParkApp {
Balloon balloon = new Balloon( ... ); }
.getColor()
.drift()
.draw()
You – User of balloon
(in other class)
know only public
details about balloon