Radio Shack TRS-80 - Page 152

Logical Variations
This next program
example
mixes
equals signs, greater
-than and
less-than in
the same pro-
gram. It determines and
reports
whether
the two numbers you
input are both positive, both
negative, or have
different
signs.
Analyze
the program.
Note the
parentheses. They
tell you
to
shift your thinking to
"logi-
cal".
Type it
in and RUN.
10 INPUT
"FIRST NUMBER IS"
;X
20
INPUT "SECOND
NUMBER IS"
;Y
30
IF (X>=0)
*
(
Y>=0)
THEN 70
40
IF
(X<0)
*
(Y<0)
THEN 90
50 PRINT
"OPPOSITE SIGNS"
60
END
70 PRINT "BOTH
POSITIVE
"
80 END
90
PRINT
"BOTH NEGATIVE"
With Graphics Too,
Yet
Yes, the logical symbols
also work
along with the
graphics
statements. See if you can
figure
out the
surprise
caused by the
logical
OR
in line
40.
Type this
program in, and RUN.
10 CLS
20 FOR X=0 TD
127
30 FOR
Y=0 TO 47
40 IF CX>=64)
*
(Y>=24)
THEN
60
50 SET (X
t
Y)
60 NEXT
Y
70 NEXT
X
150