Sharp PC-1403 - Page 153

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T h is prog r am c o nt i nues to a sk 'CO N T I N UE ?'
a s l ong a s 'YES ' is entered ; it stops i f
' NO ' is en t e r ed , a nd complains otherwise.
1 0 IN PUT " CO NTI NU E ? "; A $
20 IF A$= " Y E S" THEN GOTO 10
30 IF A$ =" N O" T H E N GOTO 60
4 0 PR I NT " Y E S O R NO , P LE ASE "
50 EN D
Examples
The statem en t which fo ll ows t he THE N m ay be any B ASI C state m e nt , in cl ud i ng
anothe r I F ... THEN, If i t is a LE T s t atem e n t , th e L E T verb i t sel f m ust a pp ea r.
The two f ormats o f t he I F statement are iden ti c a l i n act i on , bu t the f irst fo rm a t i s cl e a r.
* 1 #1
In the normal running of BASIC pr ogr a m s , s t a t e men ts ar e e xec u te d in the sequence in
which they occur . The I F . . . T H E N v e r b pa i r allow s dec i sio ns to be mad e du r i ng
exec u tion so tha t a given sta tement i s exec ute d o nl y w hen d es i red . When t he condition
part of th e I F statemen t is t rue , t he sta t emen t is e xe c u te d ; when it is false, the
stat e ment is skipped .
The condition part of the I F s t at e m e n t c an be a n y re l ation a l e xp r ession as described in
Chapter 4. I t is also poss i b l e to use a nu me ric ex p res sion as a condi tion, alt h oug h the
int en t of the statement w ill be l ess c l ear . A ny e x p r es sio n wh i ch evaluates to zero or a
nega t ive number is considered f alse; an y wh i c h e v a l uates to a p ositive nu m b er is
cons i dere d true.
•A!IM·Mi
The I F ... THEN ve r b p air is u se d to e x e c ut e o r n o t to e x ec ute a s t atemen t depending
on c onditi on s at the ti me the p r og ram i s run .
Abbreviations : non e f o r I F; T , TH . , T H E .
1 IF condition THEN s t a t eme nt
2 JF condit i on stateme n t
Verbs
IF ... THEN