game of the month
JACKS
Short elegant program for the classic kid's game
by COY ISONComputer JACKS is patterned after the children's game that most of us are familiar with. You bounce a ball and pick up a certain number of your seven jacks. The BASIC program runs on all Atari computers. Antic disk subscribers RUN "D:JACKS.BAS"
Type in the program, check it with TYPO and SAVE a backup copy.
RUN the program and plug your joystick into Port 1.
You will be prompted to touch the red fire button to throw
the jacks. Next you will be prompted to touch the red fire button
to bounce the ball. When the ball goes up into the air you must move
the cursor line and pick up a jack on the screen.
You are required to start with your one's, which means
that you need to pick up one jack and move back under the ball before it
hits the ground. After having completed this you will be allowed
to throw the jacks and bounce the ball again. This time you will
be on your two's and must continue until you have worked up to your seven's.
Pick up only the number of jacks you are on. If
you are on your three's and only pick up two jacks you must go back to
your two's. If you pick up four jacks you also have to go back to
your two's. You must also catch the ball before it hits the ground
or you will be required to go back to the previous number of jacks.
The game of JACKS is a simple concept that was an interesting
challenge to program. I hope you have fun playing JACKS - and get
better scores than I do. I've never made it to my seven's and picked
them all up!
JACKS VARIABLE LIST
A -Used to locate jacks
LP -Loop variable
X -Loop variable
OV -Cursor position (X)
DO -Cursor position (Y)
S -Joystick value (0)
DX -X Joystick movement (0,1, - 1)
DY -Y Joystick movement (0,1, - 1)
BM -Ball movement up/down
N -Add to BM (1, - 1)
JV -X Position of jacks (random)
JD -Y Position of jacks (random)
CT -Jack count picked up
H -Number of jacks holding
PU -Number of jacks picked up
SC -Start of screen memory
QQ -Locate jack position - do not over print
JACKS TAKE-APART
100- Control initialization.
110- 199 Move ball.
140- 150 If ball reaches top then (N=+l) change direction.
200- 250 Up date # need to pick up and # that you are holding.
260- 400 Joystick route - main loop.
330- 360 Check for ball collisions. Check for jack collisions. Check
for wall collisions.
370- 380 Change Over/Down variables. Print Cursor line at OV,DO.
390 Every second loop move ball one space.
410- 490 If ball is caught clear jacks up date # to pick up etc.
500- 640 Draw screen.
650- 740 Prompt to throw jacks and bounce ball.
750- 850 Random place jacks.
770 Position ball at bottom of screen.
790- 840 Place seven jacks at JV, JD. JV=over position JD=down position
820 Make sure jacks are not placed on top of each other.
900- 960 Game over - Play again?
1000-1130 Download character set and redefine new characters.
School teacher Coy Ison is a self-taught BASIC programmer Ison and his wife have written educational Programs and games for about four years.
Listing 1: JACKS.BAS Download