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 ▼ Anthony L. Mach Junior Member Posts: 28 Threads: 3 Joined: Dec 2005 12-26-2005, 01:19 AM Hello all, I always get a ton of good information and programs from the forums. Anyway, here's a present of dubious(?) value to everyone. This is what happens when you have too much time on your hands during the holidays! :) Please check it out: Check to see if the number you have entered is prime. Program gives a result of "1" if prime, or "0" if not. If the number is not prime, hitting RCL 3 will give you the square root if the number has one, or will give you the lowest factor of the number. It isn't optimized or anything, just plain jane. The original number can be recalled by hitting RCL 1. Legend: / = divide SQRT = The square root ```00- 01- STO 1 02- SQRT 03- STO 3 04- FRAC 05- X=0 06- GTO 33 07- RCL 1 08- 2 09- STO 3 10- / 11- FRAC 12- X=0 13- GTO 33 14- 3 15- STO 3 16- RCL 1 17- SQRT 18- INTG 19- STO 2 20- RCL 1 21- RCL 3 22- / 23- FRAC 24- X=0 25- GTO 33 26- RCL 3 27- RCL 2 28- X<=Y 29- GTO 36 30- 2 31- STO +3 32- GTO 20 33- 0 34- ENTER 35- GTO 00 36- 1 37- ENTER 38- GTO 00 ``` Enter positive integers only. Enjoy! Tony, AB9IO ▼ Vieira, Luiz C. (Brazil) Posting Freak Posts: 4,027 Threads: 172 Joined: Aug 2005 12-26-2005, 02:07 AM Hi, Anthony; First, congratulations for your program. Looks like being an efficient code (did not run it yet, sorry...). BTW, to which calculator has it been written? First I thought it was for the HP12C, then it came to my mind it might also fit in the HP10C. Well, based on the INTG code instead of INT, I consider that it is for the HP12C. Best regards. Luiz (Brazil) Alfredop Junior Member Posts: 6 Threads: 2 Joined: Jan 1970 12-26-2005, 09:36 AM Hi, unless I made an error in copying the program, it seems that it does not work for the primes 1, 2, and 3. Ciao Alfredo ▼ Anthony L. Mach Junior Member Posts: 28 Threads: 3 Joined: Dec 2005 12-26-2005, 12:00 PM Hi Alfredo, You are absolutely correct. The program does not report 2 or 3 as prime. It is an error that I could have easily corrected. Sorry about that. I did write it for the 12c, but it should work for all of the Voyager calcs. It will probably work for others, but [sigh] I don't have any others to work with. Thanks for the response. I've tested the program with the prime checker at math.com and gotten perfect results. All responses welcome. Tony ▼ GE Member Posts: 230 Threads: 11 Joined: Jan 1970 12-27-2005, 09:54 AM Hello, I would no call prime factorization with trial division efficient, but criticizing is easier than programming, so congratulations on your program. The 12C was probably not intended as a tool for number theory explorations... ▼ Anthony L. Mach Junior Member Posts: 28 Threads: 3 Joined: Dec 2005 12-29-2005, 03:50 AM Hi GE, You're not kidding! ;) I sometimes enjoy writing little programs for the 12C to keep my mind agile- and to have a couple of laughs. Tony

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