Chapter 1

1. Chapter 1 Introduction to Computers and Java

2. Chapter 1 1.1 Computer Basics 1.2 A Sip of Java 1.3 Programming Basics 1.4 Graphics Supplement

3. 1.1Computer Basics

4. The CPU is the brain

5. Memory is the storage

6. RAM is volatile

7. Secondary memory is permanent

8. Memory is byte addressable 4 byte memory location at address 8 bits = 1 byte

9. Programmers writeprograms

10. Computers executeprograms

11. Programs must betranslated Java code Machine code

12. Using a Compiler<Compile once – run many> Assembly codeLow level Source codeHigh level Compiler Binary codeMachine level

13. Using an Interpreter<Compile-run cycle> Assembly codeLow level Binary codeMachine level Programexecution Source codeHigh level Interpreter

14. The Java way usesboth techniques Java Virtual Machine<Interpreter>

15. A class loader combinesall the bytecode files

16. 1.2A Sip of Java

17. Text Application Deconstructed<FirstProgram.java> Program uses the scanner class import java.util.Scanner; public class FirstProgram { public static void main(String[] args) { Inform the user System.out.println("Please enter two numbers and"); System.out.println("I will compute their sum."); Declare variables int n1; int n2; Read from the keyboard Scanner keyboard = new Scanner(System.in); n1 = keyboard.nextInt(); n2 = keyboard.nextInt(); Give user an answer System.out.println("Their sum is"); System.out.println(n1 + n2); }// end main() }// end FirstProgram

18. Text Application Deconstructed<output> Please enter two numbers and I will compute their sum. 10 30 Their sum is 40

19. GUI Program Deconstructed<HappyFace.java> Classes we need for GUI programs package happyface; import javax.swing.JFrame; import java.awt.Graphics; public class HappyFaceApplet extends JFrame{ @Override public void paint(Graphics canvas) { } } Using drawing commands canvas.drawOval(100, 50, 200, 200); canvas.fillOval(155, 100, 10, 20); canvas.fillOval(230, 100, 10, 20); canvas.drawArc(150, 160, 100, 50, 180, 180);

20. GUI Program Deconstructed<HappyFace.java> Set window's initial width and height public HappyFace() { setSize(600, 400); setDefaultCloseOperation(EXIT_ON_CLOSE); }// end HappyFace() Exit program when window is closed. public static void main(String[] args) { HappyFaceguiWindow = new HappyFace(); guiWindow.setVisible(true); }// end main() }// end HappyFace Initialize the window and make it visible

21. 1.3Programming Basics

22. Java is OO

23. Objects can representmany things

24. A class providesthe blueprint

25. OOP is based onthree pillars Encapsulation Polymorphism Inheritance

26. Encapsulation = Information Hiding You can drive a car, but you may not know how an engine works.

27. Inheritance = Reuse / Extend Objects can be reused Objects can be extended

28. Polymorphism = React in own way Come back!

29. Before coding beginsdevelop your algorithms Algorithms come inmany flavors

30. Once coding beginsbe aware of bugs Syntax – Grammar not followed Run-time – Computer can't honor request Logic – Programmer slip

31. 1.4Graphics Supplement

32. The Coordinate System (0,0) X (100, 50) Y

33. Drawing an Oval (0,0) X (100, 50) Y canvas.drawOval(100, 50, 100, 100);

34. Filling an Oval (0,0) X (100, 50) Y canvas.fillOval(155, 100, 10, 20);

35. Filling an Oval (0,0) X (100, 50) Y canvas.fillOval(230, 100, 10, 20);

36. Drawing an Arc (0,0) X (150, 160) Y canvas.drawArc(150, 160, 100, 50, 180, 180);