Radio Shack TRS-80 User Manual page 170

With
HOW?
messages, the
Computer
inserts
a question
mark
right after
the
error.
For
example:
HOW?
10
PRINT
INTC
I
)
7/23
The
question
mark
tells
us that the error
was discovered during execution of the
INT
function.
We
can guess that the value for
I
probably exceeded the
allowable range for the
INT
function (value
should be
greater
than
-32768
and
less
than +32768).
Now
let's
take a look at
some
of the
common
sources of "computer-detected errors".
1.
Assume
the error
is
in
a
PRINT,
or
INPUT
statement.
Did you:
a.
Forget
one
of the
needed
pair
of quotation
marks?
Example:
10
PRINT "ANSWER
rs, X:
GOTO
5
ERROR: No
ending quotation
mark
after
I
S
b.
Use
a variable
name
other than
a single letter
of the alphabet?
Example:
10
INPUT AG.S1
ERROR: LEVEL
I
variable
names can have neither
more
than
one
letter,
nor
a letter/
number
combination.
c.
Forget
a
semicolon
or
comma
separating variables or text, or
bury
the
semicolon
or
comma
inside
quotation
marks?
Example:
10
PRINT "THE VALUE
I
S
;
"
V
ERROR:
The
semicolon
is
inside the quotation
marks
(so
the "string" of
words and
the
variable are
not
properly separated.)
d.
Forget the
line
number,
accidentally
mix
a
letter in
with the
number,
or use a
line
number
larger
than
32767?
Example:
72B3
PRINT "BAD LINE NUMBER."
L,
-ERROR
e.
Accidentally have
a
double quotation
mark
in
your text?
Example:
10
PRINT "HE SAID "HELLO THERE
."
"
How
could
we
vetify
ttiis
immediately*? Jwst«!Qiri-
m«nd
the
Computer
to
PRINT
I
(usin^ho
lifts:
'
number).
':
'\:-^
:.'„.:..'.
:',iw' /-::/ '.-:
Yes,
we
know
it's
ok
if
the missing
quote
is
the; last
ehajtseter in the
-line."
168