Author 
Message 
TheXploder

Posted: Fri Feb 20, 2004 12:39 pm Post subject: Prime Number Finder 


Here is a program that finds prime numbers (divisible by itself and 1):
code: 
var c, number : int := 0
loop
for decreasing i : number  1 .. 2
if number mod i > 0 then
c := c + 1
end if
end for
if c = number  2 then
put "Number: ", number, ", Prime number."
c := 0
else
put "Number: ", number, ", is not a Prime number."
c := 0
end if
number := number + 1
delay(10)
end loop

This could be sead up a bit, if I cancel out all numbers with a 5 or 0 at the end, or the numbers that are divisible by a previous prime number, can't be prime anymore...
I used this website to check them aswell: http://www.utm.edu/research/primes/lists/small/1000.txt
If you like please play around with it and try to beat me at finding the prime numbers: I am currently at prime number: 12739
ohh, wait: 16229






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Tony





the_short1

Posted: Sat Feb 21, 2004 11:11 pm Post subject: (No subject) 


hahah... yea Tony's prog... it worked in 12 sec to produce to 1million
produces a text file will all prime numbers in it...
from 2 > million
(with a 120 MHZ peice of crap)
WOW... that post is old too... 1y... at time when admins didnl;t have steady 2000 bits






TheXploder

Posted: Sat Feb 21, 2004 11:46 pm Post subject: (No subject) 


thanx for that program Tony...






Andy

Posted: Sun Feb 22, 2004 2:00 pm Post subject: (No subject) 


if u want a really good one, do some string manipulation, so u can store 255 digit numbers






Tony

Posted: Sun Feb 22, 2004 11:47 pm Post subject: (No subject) 


why not just use a char array then? you can make your arrays much larger then 255

Tony's programming blog. DWITE  a programming contest. 




Andy

Posted: Mon Feb 23, 2004 10:49 am Post subject: (No subject) 


good point






Andy

Posted: Mon Feb 23, 2004 10:50 am Post subject: (No subject) 


how about a flexiable array of strings?






rizzix

Posted: Tue Feb 24, 2004 11:59 pm Post subject: (No subject) 


aah but turing arrays have a limit of 1M elements.
using a string class i created will let u manipulate on an infinite number of characters. (or maybe untill u exhaust all the free memory in RAM)






Tony

Posted: Wed Feb 25, 2004 12:58 am Post subject: (No subject) 


you can always start writing numbers down on your harddrive

Tony's programming blog. DWITE  a programming contest. 




BlAcK TuRtLe

Posted: Sun Feb 29, 2004 2:34 pm Post subject: (No subject) 


This is a variation of your code which lets the user enter a number then finds out whether or not its prime.
code: 
var x, num : int := 0
loop
put "Enter a number(99 to exit)"
get num
exit when num = 99
for decreasing y : num  1 .. 2
if num mod y > 0 then
x := x + 1
end if
end for
if x = num  2 then
put num, ", is a prime number."
x := 0
else
put num, ", is not a Prime number."
x := 0
end if
delay (2000)
cls
end loop
cls







