String variables
String variables are variables which are used for storing character strings. Names assigned
to
string
variables
must
conform to the same rules as those assigned
to
numeric variables; however a dollar sign
($) is appended
to
the end
of
string variable names
to
differentiate them from
other
types
of
variables.
String variables may be used
to
store a maximum
of
255 characters. Such variables are
blank
until
string
data
is assigned
to
them.
The only
operator
which can
be
used in expressions including more than one string variable is the
"
+"
sign.
(Example:)
1 0
A$
=
11
A B C 0
11
• • • • • • • • • • • • Substitutes the character string ABCD
into
string variable A$.
2 0
B$=
11
XY
Z
11
···········
··
··
Substitutes
the
character string
XYZ"
into
string variable B$.
3 0
C$
= A
$+B$·
······· ·
··
··
··
Substitutes the sum
of
string variables A$ and B$ (ABCDXYZ)
into
string variable C$.
4 0
PR
I N T C $ · · · · ·· · · · · ·
··
· · Displays the contents
of
string variable C$.
System Variables
System variables contain values
whi<;:h
are automatically changed
by
the BASIC interpreter. The system
variables are size (the variable which indicates the amount
of
BASIC free area) and TI$ (a 6-digit variabie
which contains the value
of
the
system's 24-hour clock
).
(Examples:)
1 0 T
I$=
11
0
135
00
11
··
·This
statement assigns the value corresponding to
1:35:00
A.M.
to
system variable TI$ and sets the system clock
to
that
time.
2 0
PR
I N T T I $ · · · · · · · · · · · · Executing this statement displays the current time
of
the system
clock (24-hour time).
Display format:
13
28
1 9
...
...
. . .
..
l
ndicatesthatthet
i
meis
13:28:
19
.
PR
I N T S I Z E J · · · · · · · · · · · · · · · This displays the current
amount
of
free space in the
computer's
memory (in
other
words, the amount
of
space which is available
for additional program lines). The value indicated
by
this variable
is reduced each time a program line is entered.
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