finding prime numbers

[hsn]

i want to find the prime number in a list from 2 to 1000000
which algorithm is the best one to find the prime numbers in a really fast way.

thanks in advance

hsn

[sicarie]

What algorithms are you looking at?

[hsn]

if you have a list 2 10
i want to find an algorithm that will find the prime numbers 2,3,5,7 very fast.
but in a list 2 to 1000000 .
like sieve algorithm. but the problem is that i don't understand exactly how to implement it correctly in C++

please guys i need some guidings

hsn

[sicarie]

Okay, what parts of the sieve algorithm don't you know how to implement?

[hsn]

the loops
how to go through it exactly that what i getting some problems in understanding it.
and what should i use to delete the values from the list (what type of list should i use).

thanks

[sicarie]

Okay, well, let's make sure we're talking about the same one, first. I believe you're speaking of the Sieve of Eratosthenes ?

What parts of that don't you understand? Did you walk through the algorithm by hand for a smaller set? Like 1 - 50? Or maybe 1 to 30? Just enough so you can understand how it works?

[Menso]

A code like this won't be as fast as possible, but it will find primes with that method.

code removed, please read posting guidelines

[hsn]

yes i have tried this algorithm and walked through some examples
but when i want to code it i have some problems
i am not sure what to use. should i use vectors, dynamic arrays
i don't know exactly what to use.
and if there is an algorithm to find the prime numbers from 2 to 1000000 which is faster than sieve i would be greatful.
i am particepating in an online judge and my answer give time limit crossed
i have only 3 seconds to solve it and i pass that limit all the time.

[hsn]

i have seen that link before i post my question here. i just need some explnation in what to use in coding.