Atari XL

20
35
The Ateri XL Handbook
PRINT "AN EXTRA LINE"
Notice that the computer inserts the extra line in
the appropriate place: it is not put at the end.
NOTE
It is a good idea always to number
program lines in steps of 10 to allow
extra or forgotten lines to be inserted
without having to renumber the whole
program.
To delete a line, type the line number and press
RETURN. The line is deleted from the list in the
computer's memory.
Now see if you can alter the example program to
PRINT different words on the screen.
When you have exhausted the possibilities of this
program, you can use the command NE W to delete
the whole program. You will then be ready for the
next program.
This program will demonstrate some of the
graphics facilities of the Atari. Don't worry if you
don't understand all the BASIC commands, they
are explained later in this book.
10 GRAPHICS
9
20
SETCOLOR
4,1,0
30 FOR Y=50 TO 0 STEP
-10
40
FOR
X=O TO 24
50
LUM = X+3: IF
X>ll
THEN
LUM. =
27-X
60 Y2
=
X+Y
70 DrAM = SQR(144-(X-12)
*
(X-12»/2
80
COLOR 15-LUM
90 PLOT Y2,
Y+7-DIAM
100 DRAWTO Y2,
Y+7+DIAM
110 COLOR LUM