Radio Shack TRS-80 - Page 116

30
INPUT
"DIAGONAL
LENGTH"
;K
40 CLS
50
FOR
L
=
TO K
60
SET
CX+L.Y+L)
70 NEXT L
99
GOTO 99
Once we have the
diagonal
line, we
can
form a right
triangle
by
adding:
70
SET(X,Y+L)
80
SET<X+L,Y+K>
9
NEXT L
or
70
SET(X+K
,
Y+L)
80
SET(X+L,Y)
90
NEXT
L
Try
them
both. What is the difference in the
displays?
Answer:
They
are inverted, mirror-images of each other.
Broken
Lines
In
every graphics program we have used, we could have
made
the lines "broken" by intro-
ducing
a
STEP
other
than
"1"
in the FOR-NEXT loops. For
example,
we can get a
broken
horizontal
line with:
114