Fermat

[Desi Winda]

how to generate a large prime numbers in vb
using fermat algorithm.

[<M/>]

Ever thought about google or showing effort at least?

Here is a solution: http://www.freevbcode.com/ShowCode.asp?ID=9430

[Desi Winda]

thank you.

if i want to generate the prime number randomly, what will i do ?

[ddanbe]

Click Here

[<M/>]

This may also help: http://number.subwiki.org/wiki/Fermat_primality_test

@ddanbe, looks like your also a grumpy cat, my grumpy cat avatar is not satisfied (;D)? (looking at your profile pic compared to mine)

[tinstaafl]

how to generate a large prime numbers in vb
using fermat algorithm.

Actually using fermat algorithm, all you get is best guesses, with a high degree of probability of being prime.

[tinstaafl]

Here's a simple little function that will check if a number is prime:

Private Function CheckForPrime(ByVal Num As Integer) As Boolean
    CheckForPrime = True
    If Num <> 2 Then
        For i = 3 To Num / 3 Step 2
            If Num Mod i = 0 Then
                CheckForPrime = False
            End If
        Next
    End If
End Function

[tinstaafl]

oops, gotta stop trying to throw code together when I'm rushed for time :). Couple errors in that code this one should work better:

Private Function CheckForPrime(ByVal Num As Integer) As Boolean
    CheckForPrime = True
    If Num <> 2 Then
        If Num Mod 2 = 0 Or Num = 1 Then
            CheckForPrime = False
        Else
            For i = 3 To Num / 3 Step 2
                If Num Mod i = 0 Then
                    CheckForPrime = False
                    Return CheckForPrime
                End If
            Next
        End If
    End If
End Function