# HP Forums

Full Version: (71B) Buffon's Needle
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An extract from Buffon, [kiyoshiakima url]

"2 Simulation Programs
Buffon's Needle can be implemented easily on all but the smallest HP programmable
2.2 BASIC
For the HP-71B the following BASIC program simulates the experiment. It prompts for the number of ten-throw trials, then prints the occurrences of each outcome and an estimate for π.
10 DESTROY ALL @ OPTION BASE 0 @ RADIANS @ DIM R(11) @ P=0
20 INPUT N @ FOR I=1 TO N
30 H=0 @ FOR J=1 TO 10 @ IF RND()<SIN(RND()*PI) THEN H=H+1
40 NEXT J @ R(H)=R(H)+1 @ P=P+H
50 NEXT I
60 FOR I=0 TO 10 @ PRINT I;R(I) @ NEXT I
70 PRINT 20*N/P"

BEST!
SlideRule
(09-08-2019 04:00 PM)SlideRule Wrote: [ -> ]30 H=0 @ FOR J=1 TO 10 @ IF RND()<SIN(RND()*PI) THEN H=H+1
40 NEXT J @ R(H)=R(H)+1 @ P=P+H

You will get a syntax error entering line 30, it's just RND, without the parentheses, not RND().

Also, it should run somewhat faster if you include the NEXT J also in line 30, like this:

30 H=0 @ FOR J=1 TO 10 @ H=H+(RND<SIN(RND*PI)) @ NEXT J

(written and posted on the go using a tablet, still not at my laptop)

Regards.
V.
.
(09-08-2019 09:54 PM)Valentin Albillo Wrote: [ -> ]
(09-08-2019 04:00 PM)SlideRule Wrote: [ -> ]30 H=0 @ FOR J=1 TO 10 @ IF RND()<SIN(RND()*PI) THEN H=H+1
40 NEXT J @ R(H)=R(H)+1 @ P=P+H

You will get a syntax error entering line 30, it's just RND, without the parentheses, not RND().

Actually, RND(), with parentheses, is a valid syntax on the HP71, as for other functions without argument. Even PI can be entered as PI() since PI is a function from the HP71 system point of view.

J-F
Reference URL's
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