Part One
Lets get started writing our first Java program
Fire up Dr.Java and paste this in or type it exactly as you see here (be careful java is case sensitive):
public class Lesson0 { public static void main( String[] args ) { // prints hello world System.out.println("hello world"); } }
Save the file, hit compile and run. You should see the following:
> run Lesson0 hello world >
What did the line with System.out.println do? What did the line starting with // do?
Part Two
Now try printing Hello Again instead. Is it clear where you have to change your program?
Part Three
Try this code:
System.out.println("hello"); System.out.println("World");
Now try this:
System.out.print("hello"); System.out.print("World");
Can you spot the difference between print and println?
Part Four
Now try this code instead:
public class Lesson0 { public static void main( String[] args ) { // prints hello world System.out.println("hello\nworld"); } }
Can you tell what \n does?
Home Work
Write a program that provides the following output
A programmer started to cuss Because getting to sleep was a fuss As he lay there in bed Looping round in his head was: while(!asleep()) sheep++;
.. and if you want to learn more on your own
Figure out what \t means.
Figure out how to make a comment more than one line.
Read through the Dr.Java Book and do the exercises inside.