Texas Instruments TI-99/4A User Reference Guide

Inchworm
This program creates an inchworm that moves back and forth
across the screen. When the inchworm reaches the edge of the
screen, an "uh-oh" sounds, and the inchworm turns around to go
in the opposite direction.
. l'hese statements allow you to enter a color for the inchworm (color
codes 2·3,5-16 are recommended). The screen is then cleared. The
CALL COLOR statement assigns the color you selected to
character set 2. XDIR IS used to de,,'"ignate which directIOn the
inchworm moves (+ 1 indicates right and -1 indicates left).
This loop moves the inchworm across the screen. Line 180
computes where the next block is to be displayed and line 190
places the new block on the screen. The DELAY luup g;uvcnas how
fast the inchworm moves aCross the screen Line 220 erases the old
color block (so a continuous line won't be drawn) by placing a blank
space over the block previously displayed at XULO. Lme 2JU
saves the current block position so a new one can then be
computed. The loop is repeated until the inchworm reaches the
edge of the screen.
Line 250 reverses the direction of the inchworm. Lines 260 and
270 produce the "uh-oh" sound. Then line 280 causes the loop to be
performed again.
III·16
Examples:
>N EW
>'00 R~M lNLHWORM
>110 CALL CLEAR
>120 INPUT "COLOR? ":C
>130 CALL CLEAR
~140 CALL COlDR(2,e,C)
>150 XOLO=l
>160 XDIR=1
>170 FOR 1=1 TO 31
>180 XNEW=XDLD+XDIR
>190 CALL HCHAR(12,XNEW,42)
~2oo FOR DElAY=' TO 200
>210 NEXT DELAY
>220 CALL HCHAR(12,XOLO,32)
>230
XOLO=XtllEW
~240 NEXT 1
>250 XDIR=-XD1R
~260 CALL SOUND<100,392,2)
>270 CALL SOUNO(100,330,2)
>280 GoTo 170
>RUN
--screen cLears
COLOR? 7
--screen cLears
--inchworm moves back and
forth across the <creen
(press CLEAR to stolJ
the IJrogram)
User's Reference Guide

Texas Instruments TI-99/4A Specifications

General

Brand	Texas Instruments
Model	TI-99/4A
Category	Desktop
Language	English