Post by: Xavya on October 10, 2006, 05:21:35 PM
PS ALso i would love you for all eternity thanks
Post by: Smoke39 on October 10, 2006, 05:57:18 PM
Have an integer that keeps track of how many prime numbers you've found. Set up a while loop that goes until you've found 100 prime numbers.
Have a floating point that you increment by 1 on each iteration of the loop. This will be the current number you're checking the primeness of.
Have another counter for a nested loop. Initialize it to 2, and have the loop go until it reaches the possibly prime number(PPN from now on) - 1.
Within the nested loop, divide the PPN by the counter. If PPN/counter == int(PPN/counter), then you know that the PPN is divisible by the counter (ie, not prime) and you can break out of the loop.
After the nested loop, check if the counter reached PPN. If so, then it made it through the nested loop without breaking. That means the number's prime. Print it to the screen, or store it (whichever you're supposed to do), and increment your prime counter.
I think that'd work. No idea if that's really the most efficient way, though.
Post by: Athrun Zala on October 10, 2006, 06:13:04 PM
so, I'd say the following:
- have a variable "number" which begins at 1 (you could begin at 2 actually...) and is the number you'll verify whether it's prime or not
- create an array (or list or whatever floats your boat ^^) with as many spaces as the numbers you need (100 in this case)
- check if "number" is prime or not (reminder: prime number is one who's only divisors are 1 and itself)...if it is, save it in the array (at the last empty slot)
- increment "number" until the array is filled (ie, you have 100 prime numbers)
EDIT: awww....beaten
(seems like we had similar ideas....)
Post by: Nick DiMola on October 10, 2006, 08:14:17 PM
Post by: couchmonkey on October 11, 2006, 06:40:04 AM
Post by: Ceric on October 11, 2006, 06:51:15 AM
Post by: UltimatePartyBear on October 11, 2006, 06:57:41 AM
It isn't necessary to check to see if the possible prime is evenly divisible by every number less than itself. It's impossible for a number n to be evenly divisble by a number greater than n/2. Also, since you're skipping all the even numbers in the first place, you don't have to check past n/3. It may be possible to trim down the possibilites more if you put more thought into it.
This is right off the top of my head, so I may have overlooked something:
