1. Welcome Smith Door AP Computer Science

2. Computer Science at West Robotics Programming (RobotC) (One Semester) VEX Robotics/Engineering Computer Science I and II (Pascal) (One semester each) AP Computer Science (Java) (One year) Prepares students for the ‘A’ level exam Advanced Computer Projects (One semester, can be taken repeatedly) Developing original software Robotics Projects VEX Robotics Challenge (Mainly first semester) Spring tech conference (Second Semester)/FTC/VEX If we make the finals. Introduction to Engineering Design Design process 2 D and 3D design by hand 3D design on computer (Inventor)

3. Class Overview: First Semester Basic I/O Math in Java Decision construct For loop Java Docs and Strings While Do..while* Random Arrays of Primitives Midterm More Arrays Sorting Intro to Objects Inheritance Intro to Gridworld More OOP ArrayList Class Intro to OSI Networking model Review and Final

4. Grading Policy Grading Scale A.. 90%+ B.. 80 – <90% C.. 70 – <80% D.. 60 – <70% F.. Below 60% Assignments Programs 10 points Quizzes: 25 points Tests: 100 Points Projects: 20 to 100 points Final: 200 points or 20% of your grade, whichever is less.

5. Getting Started: Create Shortcuts Log onto the network Your password is your Student ID# followed by a period. Open MyDocuments Make a new folder for Java Keep the Java Folder open Navigate to west on 'dtcfsc04\coursework(R:)‘ Double click on SMITH_GREG folder Double click on the APJava folder Drag the R:\Smith_Greg\APJava folder from the address bar and drop it into your Java folder. Open BlueJ

6. Getting Started in BlueJ Open BlueJ Make a New Project (Folder) Create a new class (file) Start with a capital letter. Welcome1

7. Fill in the Class Delete info between the {} after the public class Welcome1 Enter your name, brief description of the program, the date and version 1.0.

8. First Program Enter the following program in BlueJ.

9. Compiling the Program Click Compile Check for errors.

10. Running the Program Right click on the class. Select void main() Click OK

11. Output Screen

12. Turn in the.java file Rename the java file to YourNameWelcome1 and turn in to the turn in folder. Include your name in the file name

13. public class Welcome1 Begins the class definition of class Welcome1 Every program must include the definition of at least one class. Class names begin with a capital letter The class name must match the file name (Welcome1.java) This is case sensitive The file must have a.java extension (BlueJ should do this for you.) Identifier rules //Series of characters (letters, numbers, digit, _, $ //Must not start with a number //Cannot be a reserved word (purple in editor) Must describe what it is storing! Java IS Case sensitive Breaking down the code. Get out your notes.

14. { Same as BEGIN in Pascal Marks the beginning of the main body of the class. Needs to match up with a } Indent between the {}

15. public static void main(String args[]) This is the starting point of every java application (Main body of the program) () after main indicate it is a method (Like a procedure) Java classes usually contain more than one method Exactly one of these methods must be called main and defined as above for the program to run. Methods perform tasks and return information. Kind of like functions void indicates that it will return nothing. String args[] is required for the main's definition. More details later.

16. System.out.println("Welcome to Java programming!"); System.out is the standard output object for showing info in the command window The stuff inside () are the arguments System.out.println(); Displays the arguments and returns to the next line Like writeln in Pascal "Wel..." This is a String of characters, message or string literal.

17. Comments and Common Errors When successfully compiled it creates a Class file for Welcome1 called Welcome1.class This file contains the byte codes that represent this application Some common errors "bad command or file name", "javac: command not found", ""'javac' is not recognized as an internal or external command, operable program or batch file" Try: The system's path environment was not set properly. Check java.sun.com/j2se/5.0/install.html “Public class ClassName must be defined in file called ClassName.java" Try: Checking that the file name exactly matches the class name.

18. Review // Mr. Smith // First Program // Today’s date public class Welcome1 { //main method begins execution of Java application public static void main(String [] args) {//The start of the method System.out.println("Welcome to Java programming!"); }//End of method main } //End of class Welcome1

19. More on System.out public class Welcome1 { //main method begins execution of Java application public static void main(String [] args) {//The start of the method System.out.print("Welcome to "); //Stays on the same line System.out.println(“Java programming”); }//End of method main } //End of class Welcome1

20. Showing Multiple lines public class Welcome1 { //main method begins execution of Java application public static void main(String [] args) {//The start of the method System.out.println(“Welcome \nto \nJava \nprogramming”); }//End of method main } //End of class Welcome1

21. Escape Sequences \ is an ‘escape’ character Some Common Escape Sequences \n for new line \t horizontal tab \r Carriage return, but on the same line \\ used to print the \character \” Used to display “

22. Displaying Formatted Text (printf) public class Welcome1 { public static void main(String [] args) {//The start of the method System.out.printf(“%s\n%s\n”,"Welcome “,” to Java programming!"); }//End of method main } //End of class Welcome1 System.out.printf(Format String, Comma separated data to display) Format String Can contain fixed text, escape sequences and format specifiers Format Specifiers: Begin with % %s is a place for a string.

23. System.out.printf( “format-string” [, arg1, arg2, … ] ); Format String: Composed of literals (String characters) and format specifiers (%d, %-,.2f Arguments are required only if there are format specifiers in the format string. Format specifiers include: flags, width, precision, and conversion characters in the following sequence: % [flags] [width] [.precision] conversion-character ( square brackets denote optional parameters )

24. Flags % [flags] [width] [.precision] conversion-character ( square brackets denote optional parameters ) Flags: - : left-justify ( default is to right-justify ) + : output a plus ( + ) or minus ( - ) sign for a numerical value 0 : forces numerical values to be zero-padded ( default is blank padding ), : comma grouping separator (for numbers >= 1000) : space will display a minus sign if the number is negative or a space if it is positive

25. Width % [flags] [width] [.precision] conversion-character ( square brackets denote optional parameters ) Specifies the field width for outputting the argument and represents the minimum number of characters to be written to the output. Include space for expected commas and a decimal point in the determination of the width for numerical values.

26. Precision % [flags] [width] [.precision] conversion-character ( square brackets denote optional parameters ) Used to restrict the output depending on the conversion. It specifies the number of digits of precision when outputting floating-point values. Numbers are rounded to the specified precision.

27. Common Conversion Characters % [flags] [width] [.precision] conversion-character ( square brackets denote optional parameters ) d : decimal integer [byte, short, int, long] f : floating-point number [float, double] c : character Capital C will uppercase the letter s : String Capital S will uppercase all the letters in the string n : newline Platform specific newline character- use %n instead of \n for greater compatibility

28. Examples % [flags] [width] [.precision] conversion-character ( square brackets denote optional parameters ) System.out.printf("Total is: $%,.2f%n", dblTotal); System.out.printf("Total: %-10.2f: ", dblTotal); System.out.printf("% 4d", intValue);

29. More Examples: Controlling integer width with printf printf("%3d", 0); 0 printf("%3d", 123456789); 123456789 printf("%3d", -10); -10 printf("%3d", -123456789); -123456789 The %3d specifier means a minimum width of three spaces, which, by default, will be right-justified

30. Left-justifying printf integer output printf("%-3d", 0); 0 printf("%-3d", 123456789); 123456789 printf("%-3d", -10); -10 printf("%-3d", -123456789); -123456789 To left-justify integer output with printf, just add a minus sign ( - ) after the % symbol, like this:

31. The printf zero-fill option printf("%03d", 0); 000 printf("%03d", 1); 001 printf("%03d", 123456789); 123456789 printf("%03d", -10); -10 printf("%03d", -123456789); -123456789 To zero-fill your printf integer output, just add a zero ( 0 ) after the % symbol, like this:

32. printf integer formatting DescriptionCodeResult At least five wideprintf("'%5d'", 10); ' 10' At least five-wide, left- justified printf("'%-5d'", 10); '10 ' At least five-wide, zero- filled printf("'%05d'", 10); '00010' At least five-wide, with a plus sign printf("'%+5d'", 10); ' +10' Five-wide, plus sign, left- justified printf("'%-+5d'", 10); '+10 ' As a summary of printf integer formatting, here ’ s a little collection of integer formatting examples. Several different options are shown, including a minimum width specification, left-justified, zero-filled, and also a plus sign for positive numbers.

33. printf - floating point numbers DescriptionCodeResult Print one position after the decimal printf("'%.1f'", 10.3456); '10.3' Two positions after the decimal printf("'%.2f'", 10.3456); '10.35' Eight-wide, two positions after the decimal printf("'%8.2f'", 10.3456); ' 10.35' Eight-wide, four positions after the decimal printf("'%8.4f'", 10.3456); ' 10.3456' Eight-wide, two positions after the decimal, zero-filled printf("'%08.2f'", 10.3456); '00010.35' Eight-wide, two positions after the decimal, left- justified printf("'%-8.2f'", 10.3456); '10.35 ' Printing a much larger number with that same format printf("'%-8.2f'", 101234567.3456); '101234567.35'

34. printf string formatting DescriptionCodeResult A simple stringprintf("'%s'", "Hello"); 'Hello' A string with a minimum length printf("'%10s'", "Hello"); ' Hello' Minimum length, left- justified printf("'%-10s'", "Hello"); 'Hello '

35. Quick Review Starting a project in BlueJ Open BlueJ Select your workspace (Folder) Project->New Project Click on ‘Class’ to create a class Double click on icon to edit the code Parts of your program public class FormattedPrint { public static void main(String [] args) {//The start of the method System.out.printf("%s\n%s\n","Welcome "," to Java programming!"); }//End of method main } Time to get started.

36. Your first programs Poem/Song: (YourNamePoem-Song) Create or modify a poem or song to display from your Java Program. You will need to incorporate at least one printf. Check: Using printf (YourNameCheck) No input Display information on the screen for a check with your generous donation to the West Salem Robotics Club. You will need to incorporate at least one printf.