Sharp PC-1500A Instruction Manual page 86

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10 PAUSE " SPECIFY T AX TA BLE TO USE :"
20 PAUSE
"(1)
SI NG LE , "
30 PAUSE "(2) MARRIED."
40 INPUT "(3) BUSI NESS ?"; TT
50 IF (TT< 11 OR (TT> 3) THE N 10
60 REM USE APPROPRIATE TAB LE
70 I F T T = 1 THEN 220
80
I F TT =
2
T HEN 300
90 IF TT = 3 T HEN 450
(etc)
Using the ON statement •Ne can consolidate lines 70, 80. and 90 into a sir1gle statem ent :
70 ON T T GOTO 220,
300, 450
ON ERROR GOTO
Using another lofm o f con trolled transfer allows a p rogram to detect when an error occu rs.
Afte r d etec tion. the program may execute statements
v~hich
attempt to recover from th e error.
Such statements may inform and ir)struct the user, or they may save valuable data.
T he ON ERRO R GOTO statements instructs SHARP where to go upon detecting the
occurrence of a1'I error. The fo rm of this st a tement is:
ON ERROR GOTO l ine·number
where line·number is the number o f
a
program line containing instructions to be
followed
in
the
event of an e rror.
F. DISPLAY PROGRAMMING
The displ ay window incorporated into the PC·1500A is a remarkably flexible ou tput device. To
allow programmers to exploi t the 1 ull po .. ver of t he
d isplay
several new statem en ts have been
added to the di alect of BASIC used by the PC·l SOOA. These extensions
aro
d'escribcd i n this
section .
The display itself util izes liquid crystal techn ology to d isp lay up to 26 chara c ters at a t irne.
Each character in t he computer's ch aracter set occ•upics a 5 x 7 do t matrix. Utiliz ing the GPRINT
command , programme rs may develop a nd disp lay thei r
o\~Jn
characters.
For graphic pu rposes, the entire display field may
be
uti l ized as a
7
x 156 dot matrix.
Individual dots within any of 156 columns may be energized to create graphics, f igures, or special
symbols. The POINT command allows "sensing"" of any column to discover which dots are
currently energized .
A speaker and tone generator allow the programmer to add the dimension of sound to t he
man-machine interac tion. Tones may
be
created a t any of 256 frequencies {range 230Hz to about
7KHi }. Automatic repeti tion of a tone and co nilrol of the duration of a tone are also possible
u nder program control.
F.1. BEEP
The
BEEP
statement allows the programmer t(.> crea te tones for game playing, error signalling.
and other in teractive applications. Th e format of the BEEP statement which creates sound is:
BEEP expression 1 , exp ression 2 , expre ssion3
8:4
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