AMSTRAD cpc 6128 User Instruction page 114

Now to the matter of saving the contents of the variables so that they can be loaded
back in when the program is run. Part 7 of the Foundation course explained how to
save the program itself, using the S A V E command. However the program itself is
only a framework which lets the variable values be put in (at the keyboard) and taken
out (at the screen). When you S A V E the program, you are saving only that
framework, not the values of the variables.
Hence we must write a section of program that will save the values of the variables
onto disc. We do this by creating a separate 'data file'.
First we 0 PEN an 0 U Tput file and specify a name for it such as "d a t a". Then we
WRIT E the values of the variables N A ME $ (x) and T E L$ (x) from 1 to 100, into
the file, and finally we CL 0 SE the 0 U Tput file and RE T URN to the menu. Let's add it
to the program from line
350
onwards. To save us typing in each new line number,
we'll use the command:
AUTO 350
., .. which will start AUT Omatic line numbering from the required line:
350 OPENOUT "data"
360 FOR, x=1 TO 100
370 WRITE #9,NAME$(x),TEL$(x)
380 NEXT
390 CLOSEOUT
400 PRINT "data saved"
410 RETURN
After you have typed in line
410
and pressed [RETURN], press [ESC] to stop the
AUT Omatic line numbering.
Now we need to add an extra number to the list of numbers in the 0 N m s GO SUB
command in line 1
00.
This is because we have added another option for the menu to
select. Therefore E D I T line 1
00
to add this extra number:
100 ON ms GOSUB 120,210,270,350
Now, whenever you select menu option number 4, the program will save all the
information that you entered, onto disc.
Notice that in line 3
70,
where the program W R I T E s the values of N A M E
$ (
x) and
T E L
$ (
x ) onto disc, the expression
#
9 is used after the word W R I T E. The
#
sign is a
'stream director', in other words, it tells the computer which 'stream' to send the data
to. The computer has 10 streams:
Directing data to streams 0 to 7
(#
0
to
#
7) will result in it appearing on the screen
because streams
#
0
to
#
7 are 'screen streams' or WIN DO W s.
Beyond Foundations
Chapter 2 Page 9