Fixed Variables - Sharp PC-1403 Operation Manual

79
This means that you have put numeric data into the area of memory called A and then
told the computer to show you that information again as STRING data. Thi s confuses
the computer so it says that there is an error condition. Press the ~ key to clear the
error condition. Now try the following example:
A$
=
"ABC"
I
ENTER
I
A
I
ENTER
I
ERROR 9
Fixed
Variables
The first section, fixed variables, is always used by the computer for storing data. It can
be thought of as pre-allocated variable space. In other words, no matter how much
memory your program uses up, you will always have at least 26 variables to choose
from to store data in. This data can be one of two types: NUMERIC or STRING
(alphabetic character). Fixed memory locations are eight bytes long and can be used
for only one type of data at a time. To illustrate this, type in the following examples:
A= 123
[ENTER)
A$
[ENTER)
You get the message:
Numeric
variables
Fixed numeric variables (A to Z)
Simple numeric variables (AB, C1, etc.)
Numeric array variables
Fixed character variables (A$ to Z$)
Simple character variables (BB$, C2$, etc.)
Character array variables
String
variables
Variables
S II II
To illustrate this, key in
B
lsH1FTI [l[]
=
lsH1FTI
rwi
BYTE [sH1nl
I
Wl
I
ENTER].
The value BYTE is now stored in the variable 8$. To make sure of this, type in
B I
SHIFT
I
d:J
I
ENTER).
The screen shows BYTE. This time the display is on the left side of the
screen, instead of the right.
Variables handled by the SHARP COMPUTER are divided i n to the following;
So far, we've only discussed numeric variables. What about storing alphabetic
characters? Well, the idea is the same, but, so the computer will know the difference
between the two kinds of variables, add a$ to the variable name. For instance, let's
store the word BYTE in the variable 8$. Notice the$ after the B?
This tells the computer that the contents of the letter
B
are alphabetic, or string data.
Concepts and Terms of BASIC