Radio Shack TRS-80 Model III - Page 128

TRS-80
MODEL III
The ASCII code
for
O
is
79;
for
D
it's
68.
If while making
the comparison,
BASIC reaches the end
of one string before
finding
non-matching characters,
the shorter string is
the precedent. For
example:
"TRAIL"
<
"TRAILER"
Leading and
trailing blanks
are significant. For
example:
"
A"
< "A"
ASCII for the space
character is
32;
for A, it's
65.
"Z-80"<"Z-80A"
The string on the left
is four characters
long; the string on the right is five.
How
to Use Relational
Expressions
Normally,
relational expressions are
used as the test in an IF/THEN
statement.
For
example:
IF
A
=
1 THEN PRINT
"CORRECT-
BASIC tests
to
see if A is
equal to 1. If it is, BASIC prints
the message.
IF
A$
<
B$ THEN 50
If string
AS alphabetically precedes string
B$, then the program
branches
to
line
50.
IF R$
=
"YES" THEN PRINT
A$
If
R$ equals YES then the message stored
as A$ is printed.
However,
you may also
use relational expressions simply
to return the
true or
false
results of a test. For
example:
PRINT
7=7
Prints
—
1 since the
relation tested is true.
PRINT
"A" > "B"
Prints because the
relation tested is
false.
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