Sharp PC-1403

9 8
I n a ddi ti on to execut ing different p rog r a m s b y g i v i ng their s t art i ng l in e nu mb er , y ou can
g i ve p r o grams an al ph abet ical n a m e an d start t hem wi t h the ~ k e y ( see C h ap t er
6) .
Se v er al n e w f e atu r e s ar e co nta i n ed i n th is program . T he WA I T v erb in lin e 1 00 co n tro l s
t h e l e ngt h o f time tha t disp l a y s are h e l d be f o r e the p ro gram co n t i nu e s . The n u m bers
and t h eir fa ct or i a l s a r e disp l ayed as they ar e c om p u te d . T h e t i me t hey app e ar on t h e
d is pl a y is s et by the WA I T sta t ement t o approxi m at e l y 2 s ec o n ds , instead of waiting fo r
y ou to press I E NT E R I .
A lso i n line 1 00 , n o t i c e th at th e r e a r e tw o sta t e m en t s on the s ame l ine sep arat ed by a
c olo n ( : ) . You m a y put as many sta temen t s as you wish on one line , separat i ng
each by a colon , up to t he SO - char a c t e r ma xi mum including I ENTER I . Mu lt i p l e
s t a t e ment li ne s can make a pr ogra m h ar d t o re ad and m od i fy , h owe v e r , so i t is a good
progr a m m i n g prac t i ce t o use the m only w h e re t h e sta t ements are very si m pl e o r t here i s
so m e specia l reason t o wa nt the s t a t em ents on one l i ne .
Al s o i n t h i s program , we h ave used the FO R v e r b i n l i n e 1 20 and t h e N E X T verb i n l i n e
1 50 to c r ea te a lo o p . In E xampl e 3 , yo u created an " i n finite " l oop wh i ch kept
re p eating t h e s tat e me n t s inside t h e l oo p u nt il you pressed the ~ key . Wi t h th e F OR/
N EX T l oo p , the co m pu t e r a dd s 1 t o N ea ch t i me e x ecu t i o n rea c hes the N E XT ve r b . It
the n tests to see i f N is larger than t h e li m i t L. I f N i s le s s th an or equa l t o L , ex e c u tio n
re t urn s to t he to p of th e l oop a nd th e s t a t e m e nt s a re e x ec ut ed again . If N is gr ea t er t ha n
L, exec u tio n c on tinues wit h l ine 1 60 and t he pr ogram s to p s .
Y o u may u s e any n u me r ic v ar i ab l e i n a FOR/ N E XT l oop . You al so d o n ot have t o s t a rt
co u nt i ng a t 1 a nd you c an ad d any a m ou n t a t each s t e p . See C hapte r 8 for d etails .
We h a v e lab e led this p r og r a m w ith li ne nu m be r s sta rt i n g w i t h 100 . L ab e li n g programs
w i t h d iff ere n t line n u mber s all ow s you to ha v e se v era l pr o g r ams in m emory at one ti me .
To R UN th i s progra m i nst e a d of t he on e at l ine 10 en t er :
RUN 100
A l t h oug h t h e co m puter h as a f ac t or i a l fu n c t ion , we will u s e an examp l e of t he fact o r ia l
com p utat i on in t h i s s e ction t o ex pl ai n mo r e c om p l ex progra m m i n g . · T he fo l low ing
program c om p u tes N F a c tor i a l ( N ! ) . T he p r og r am b eg i n s with 1 a nd compu t es N! u p
t o t h e l i mit which you ente r . E nter th i s p rogram .
1 0 0 F = 1 : WA I T 1 18
11 0 I N P U T " LIM I T ?" ; L
1 20 FO R N = 1 T O L
130 F = F*N
1 4 0 PR I NT N , F
1 50 NE XT N
1 6 0 E N D
Example 4- More Complex Programming
Program mi ng th e Comp u te r