Java Syntax and Output Java Part 3. public class CompSci { } All Java programs start with a class.

Java Syntax and OutputJava Part 3

public class CompSci{

}

All Java programs start with a class.

public class CompSci{ public static void main(String[] args) { System.out.println("Comp Sci!"); }} OUTPUT

Comp Sci!

public class CompSci{ //open brace

public static void main(String[] args) { System.out.println("Comp Sci!"); }} //close brace

Braces – You gotta have ‘em! Every classand every method must have a { and a } .

© A+ Computer Science - www.apluscompsci.com

public class CompSci{ public static void main(String[] args) { System.out.println("Comp Sci!"); }}

You must put a semi-colon at the end of all Java program statements ( ; ).

Never put a ; before an open { brace

;{ //illegal}; //legal

Indentation

public class CompSci{ public static void main(String[] args) { System.out.println("Comp Sci!"); }}

Indent all code 3 spaces to make it easier to read.

Java Output

System.outfrequently used methods

Name Use

print(x) print x and stay on the current line

println(x) print x and move to next line down

printf(s,x) print x according to s specifications

System.out.print("compsci");

reference command / method

OUTPUTcompsci

System.out.print("compsci");System.out.print("compsci");

OUTPUTcompscicompsci

System.out.println("compsci");

OUTPUTcompsci

System.out.println("compsci");System.out.println("compsci");

OUTPUTcompscicompsci

System.out.println("c\tompsci");

\n newline\t tab\r carriage return\b backspace

OUTPUTc ompsci

System.out.println("com\tpsci");

OUTPUTcom psci

\n newline\t tab\r carriage return\b backspace

System.out.println("comp\nsci");

OUTPUTcompsci

\n newline\t tab\r carriage return\b backspace

\\ outs \\" outs "\’ outs ’

System.out.println("\\compsci\"/");

OUTPUT\compsci"/

\\ outs \\" outs "\’ outs ’

System.out.println("\\'comp\'sci\'/");

OUTPUT\'comp'sci'/

© A+ Computer Science - www.apluscompsci.com

Escape Sequencesfrequently used combinations

Name Use

\t tabs over five spaces

\n moves to front of next line

\b deletes previous character

\r moves to front of current line

\\ nets one backslash \

\" nets one double quote "

\’ nets one single quote ’

© A+ Computer Science - www.apluscompsci.com

// single-line comments/* */ block comments

//this line prints stuff on the screenSystem.out.println("stuff");

Review: AboutMe Part1Create an AboutMe app that displays

your first name and last initial, your instructor’s name, and your school name on 3 separate lines.

Below the personal information, display a phrase that encourages your school team, such as “Go Plainsmen!”. Be sure this phrase is enclosed in quotations marks in your output.

// single-line comments/* */ block comments

/* this line prints stuff on the screen*/System.out.println("stuff");

© A+ Computer Science - www.apluscompsci.com

System.out.printf("%s","compsci\n");

OUTPUTcompsci

format()

© A+ Computer Science - www.apluscompsci.com

Review: AboutMe Part2Modify your app to include your

timetable with start and end times for each class.

Include code to properly align the data into 2 columns with the courses left aligned and the times right aligned.

Use the format() method for this.