1. CS1101: Programming Methodology http://www.comp.nus.edu.sg/~cs1101x/
What lies within CS1101?

2. Java Appreciation Java Appreciation What’s In Store In CS1101? OR
by Aaron Tan
28 July 2008, 9am, LT16
What's in store in CS1101?
What lies within CS1101?

3. Exercising Your Choice
CS1101 or
CS1101S
Java
Scheme
What's in store in CS1101?
What lies within CS1101?

4. CS1101: Course Description
“This module introduces the fundamental concepts of programming from an object-oriented perspective, and is perceived as the first and foremost introductory course to computing.”
No prior experience is assumed.
What's in store in CS1101?
What lies within CS1101?

5. CS1101: Objectives
Learning about programming methodology and principles, using the object-oriented model.
Outcomes:
Know how to solve simple algorithmic problems.
Know how to write good small programs.
JAVA is merely a tool.
This is not a course on just JAVA alone!
What's in store in CS1101?
What lies within CS1101?

6. CS1101: Lecture Groups Group X (3 lecture groups):
Mr Aaron Tan Tuck Choy (Module coordinator)
For students with more experience
Group Y (3 lecture groups):
A/P Wynne Hsu
Dr Razvan Voicu
A/P Lee Mong Li
Group Z (3 lecture groups):
A/P Tan Chew Lim
Dr Anthony Fang
Mr Henry Chia
CS1101X, Y and Z all cover the same syllabus, and have common tests.
Final grading of CS1101X, Y and Z is done together as a single group.
What's in store in CS1101?
What lies within CS1101?

7. Module Website http://www.comp.nus.edu.sg/~cs1101x/
What's in store in CS1101?
What lies within CS1101?

8. Workload (5 MCs) Lectures: Discussion: Continual assessment:
3 hours/week in a lab setting.
Discussion:
2 hours/week in a lab setting.
Continual assessment:
Lab assignments
Mid-term test
Practical Exam
What's in store in CS1101?
What lies within CS1101?

9. Skills Set (1/2) Java constructs Problem solving Program
What's in store in CS1101?
What lies within CS1101?

10. Skills Set (2/2) Java constructs (transferable skills)
Class and objects; types and variables; control constructs (selection, repetition); APIs; arrays; exceptions; applications (searching, sorting).
Problem solving (more transferable skills)
Programming methodology (development cycle, top-down design, modularity); testing and debugging; abstraction.
Others
Software tools (editor, compiler, debugger, CourseMarker); mathematical maturity.
What's in store in CS1101?
What lies within CS1101?

11. A Java Program (Hello.java)
Comments
// Display a message.
public class Hello {
public static void main(String[] args) {
System.out.println("Hello World!! :-D"); }
Class name
Method name
Method body
Output
What's in store in CS1101?
What lies within CS1101?

12. A Java Program (Welcome.java)
API package
// Author: Aaron Tan
// Purpose: Ask for user’s name and display a welcome message.
import java.util.*;
public class Welcome {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("What is your name? ");
String name = scanner.next();
System.out.println("Hi " + name + ".");
System.out.println("Welcome to CS1101!\n"); }
Creating a Scanner object
Input
An object of class String
What's in store in CS1101?
What lies within CS1101?

13. Object-Oriented Programming (OOP)
The fundamental OOP concept:
An object-oriented program uses objects.
Demo on BlueJ:
Illustrate concepts of object and class
Creation of objects
Sending messages to objects
What's in store in CS1101?
What lies within CS1101?

14. Objects and classes (1/2)
Object-oriented language
Models real-world objects you find in everyday life.
Objects
Represent ‘things’ from the real world, or from some problem domain (“that red 1200cc Honda car”, “my 2-year old Persian cat with a short tail”).
Have name, state (set of values for its attributes) and behaviors (via methods).
Perform actions or interact by sending messages.
Classes
Represent all objects of a kind (“car”, “cat”).
A class is a model/blueprint/prototype for an object. An object is an ‘instance’ of a class. Many instances (objects) can be created from a single class.
What's in store in CS1101?
What lies within CS1101?

15. Objects and classes (2/2)
Class is a concept; object is a concrete entity.
A class defines what attributes an object has, but each object stores it own set of values, which contribute its state.
Example: PlayingCards is a class, whose properties are rank and suit. The queen of clubs and nine of diamonds are two instances (objects) of this class.
New class (type of objects) can be derived from an existing class.
Superclass and subclass: the subclass extends/specializes the functionality of the superclass and inherits the properties and behaviors of the superclass.
What's in store in CS1101?
What lies within CS1101?

16. BlueJ Designed at Monash University, Australia.
Runs on top of Sun Microsystems’ Java Development Kit (JDK).
Provides an Integrated Development Environment (IDE) with editor, compiler and debugger.
Simple user interface, easy to use. Do not need to write complete application.
Refer to course website (click on “Resources…”  “Online”)
Download BlueJ and its documentation.
What's in store in CS1101?
What lies within CS1101?

17. BlueJ: Creating objects (1/4)
Choose example shapes.
Classes: Square, Circle, Triangle, Canvas.
What's in store in CS1101?
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18. BlueJ: Creating objects (2/4)
Creating a new object
Right click on Circle class and choose new Circle() to create a new Circle object. Circle() is a constructor.
What's in store in CS1101?
What lies within CS1101?

19. BlueJ: Creating objects (3/4)
Creating a new object
What's in store in CS1101?
What lies within CS1101?

20. BlueJ: Creating objects (4/4)
Creating a new object
A new Circle object circle1 is created.
What's in store in CS1101?
What lies within CS1101?

21. BlueJ: Calling methods (1/3)
Methods implement the behavior of the objects.
Right click on the circle1 object and select the makeVisible() method.
What's in store in CS1101?
What lies within CS1101?

22. BlueJ: Calling methods (2/3)
Methods implement the behavior of the objects.
Experiment with other methods: makeInvisible(), moveDown(), moveRight().
What's in store in CS1101?
What lies within CS1101?

23. BlueJ: Calling methods (3/3)
Methods with parameters:
changeColor(newcolor), changeSize(newDiameter), moveHorizontal(distance).
What's in store in CS1101?
What lies within CS1101?

24. BlueJ: State (1/2)
State: the set of values of all the attributes of an object.
Right click on the circle1 object and select the Inspect function.
What's in store in CS1101?
What lies within CS1101?

25. BlueJ: State (2/2)
Objects of the same class have the same fields/attributes. But each object may have it own set of values for its attributes.
State of circle1 object.
Fields:
int diameter
int xPosition
int yPosition
String Color
boolean isVisible
What's in store in CS1101?
What lies within CS1101?

26. BlueJ: Source code (1/8)
Right click on class Circle and select “Open Editor”.
import java.awt.*;
import java.awt.geom.*;
/**
* A circle that can be manipulated and that draws itself
* on a canvas.
Michael Kolling and David J. Barnes
(15 July 2000) */
public class Circle {
private int diameter;
private int xPosition;
private int yPosition;
private String color;
private boolean isVisible;
What's in store in CS1101?
What lies within CS1101?

27. BlueJ: Source code (2/8)
// Create a new circle at default position with default color.
public Circle( ) {
diameter = 30;
xPosition = 20;
yPosition = 60;
color = "blue";
isVisible = false; }
// Make this circle visible. If it was already visible, do nothing.
public void makeVisible( )
isVisible = true;
draw( );
// Make this circle invisible. If it was already invisible, do nothing.
public void makeInvisible( )
erase( );
What's in store in CS1101?
What lies within CS1101?

28. BlueJ: Source code (3/8) // Move the circle a few pixels to the right.
public void moveRight( ) {
moveHorizontal(20); }
// Move the circle a few pixels to the left.
public void moveLeft( )
moveHorizontal(-20);
// Move the circle a few pixels up.
public void moveUp( )
moveVertical(-20);
// Move the circle a few pixels down.
public void moveDown( )
moveVertical(20);
What's in store in CS1101?
What lies within CS1101?

29. BlueJ: Source code (4/8)
// Move the circle horizontally by 'distance' pixels.
public void moveHorizontal(int distance) {
erase( );
xPosition += distance;
draw( ); }
// Move the circle vertically by 'distance' pixels.
public void moveVertical(int distance)
yPosition += distance;
What's in store in CS1101?
What lies within CS1101?

30. BlueJ: Source code (5/8)
// Slowly move the circle horizontally by 'distance' pixels.
public void slowMoveHorizontal(int distance) {
int delta;
if (distance < 0)
delta = -1;
distance = -distance; }
else
delta = 1;
for (int i = 0; i < distance; i++)
xPosition += delta;
draw( );
What's in store in CS1101?
What lies within CS1101?

31. BlueJ: Source code (6/8)
// Slowly move the circle vertically by 'distance' pixels.
public void slowMoveVertical(int distance) {
int delta;
if (distance < 0)
delta = -1;
distance = -distance; }
else
delta = 1;
for (int i = 0; i < distance; i++)
yPosition += delta;
draw( );
What's in store in CS1101?
What lies within CS1101?

32. BlueJ: Source code (7/8)
// Change the size to the new size (in pixels).
// Size must be >= 0.
public void changeSize(int newDiameter) {
erase( );
diameter = newDiameter;
draw( ); }
// Change the color. Valid colors are "red", "yellow",
// "blue", "green", "magenta" and "black".
public void changeColor(String newColor)
color = newColor;
What's in store in CS1101?
What lies within CS1101?

33. BlueJ: Source code (8/8)
// Draw the circle with current specifications on screen.
private void draw( ) {
if (isVisible) {
Canvas canvas = Canvas.getCanvas( );
canvas.draw(this, color,
new Ellipse2D.Double(xPosition, yPosition,
diameter, diameter));
canvas.wait(10); }
// Erase the circle on screen.
private void erase( )
canvas.erase(this);
What's in store in CS1101?
What lies within CS1101?

34. Problem Solving (1/3) Problem  Algorithm Program Task 1: Anagram
Text that is formed by rearrangement of letters.
Examples:
Dear =
Astronomer =
The Eyes =
The Morse Code =
A Decimal Point =
Read
Moon Starer
They See
Here Come Dots
I’m A Dot In Place
What's in store in CS1101?
What lies within CS1101?

35. Problem Solving (2/3) Task 2: Maze What lies within CS1101?
What's in store in CS1101?
What lies within CS1101?

36. Problem Solving (3/3) Task 3: Sudoku What lies within CS1101?
What's in store in CS1101?
What lies within CS1101?

37. Think About It This set of slides will be available at
Administrative and registration issues
Please attend Course Briefing later – important!
LT17, 28 2pm
(after Dean’s Welcome Tea)
Questions?
What's in store in CS1101?
What lies within CS1101?

38. End of file
What's in store in CS1101?
What lies within CS1101?