Commodore CBM - Page 117

List the program and check the new line for any errors.
LI:,H
90 PRINT "HIT A KEY"
1 (10 GET C$: 1F C$="" GOTO 1 ܀1
110 PF.: 1 NT "::1".;
120 FOF.: 1=1 TO :,::4(1
130 PF.: nn C$.;
140 NE::·::T
1 50 PR 1 ~n "PHEI,J 1 "
F.:EAD'r'.
Now when vou run the program it gives instructions for using it. so vou are
sure of
what ta do. Run the program several times ta display different characters
and note how
much easier the program is ta use.
There is one important modification left to make. You will want to run the
program more than once -
that is. display a character. then display another
one. etc. By modifying the program to go back to its beginning
point instead of
ending. vou
won't have to type in RUN each time. Add a line at the end of the pro-
gram ta
jump back to the beginning of the program:
160 GOTO 90
Again. display the program and check the new line.
LIST
9(1 PRINT "HIT A KEY"
10€1 GET C$: 1 F C$="" GUTO 1 C10
11(1 PRIt·n ":')".;
120 FOR 1=1 TU 840
130 PRHn C$.;
140 ~jE>~T
150 F'F.: 1 NT "PHEI~!"
160 GOTO 9(1
READ'T'.
m
Now it is even easier to use the program. Enter RUN and follow directions.
Of course. vou have ta use the STOP key ta exit from the program. This
can be eliminated by programming for one particular key.
wh en pressed as a
data key.
ta signal termination of the program, For example. if the RETURN key
were pressed instead of a data key. the program could end. To do this. add a
check for carriage retu
rn after a key has been pressed.
For ail data keys. as weil as the cursor control keys. vou can check for a
key
as a string literai. For example. to branch to statement 200 if the Y key is
pressed. Vou would enter the following statements:
1(1(1 CiET C$: 1F C$="" GOTO 1 (1ü
1 (15 1F C$=" 'T'" CiOTO 200
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