Foro de elhacker.net

Public Function IsItPrime(ByVal lNumber As Long) As Boolean
    Dim i       As Long
 
    If (lNumber > 2) And (lNumber Mod 2) Or (lNumber = 2) Then
        For i = 2 To (lNumber ^ 0.5)
            If (lNumber Mod i) = 0 Then
                GoTo Exit_
            End If
        Next i
        IsItPrime = True
    End If
Exit_:
End Function

'0 ---> Invalido
'1 ---> No Primo
'2 ---> Primo
Option Explicit
Private Function Check_Prime_Number(ByVal lNumber As Long) As Byte
    Dim x            As Long
    If lNumber >= 2 Then
        Check_Prime_Number = 2
        For x = 2 To (lNumber ^ 0.5)
            If (lNumber Mod x) = 0 Then
                Check_Prime_Number = 1
                Exit For
            End If
        Next
    End If
End Function

Public Function IsItPrime(ByVal lNumber As Long) As Boolean
    Dim i       As Long
 
    If (lNumber > 2) And (lNumber And 1) Or (lNumber = 2) Then
        For i = 3 To Sqr(lNumber) Step 2
            If (lNumber Mod i) = 0 Then GoTo Exit_
        Next i
        IsItPrime = True
    End If
Exit_:
End Function

Public Function Check_Prime_Number(ByVal lNumber As Long) As Boolean
    Const sPrimeDigit            As String = "1379"
    Dim sLastDigit               As String * 1
    Dim sNumber                  As String
    Dim x                        As Long
 
    If (lNumber > 2) Then
        sNumber = Str$(lNumber)
        sLastDigit = Right$(sNumber, 1)
        If InStr(sPrimeDigit, sLastDigit) > 0 Then
            For x = 3 To Sqr(lNumber) Step 2
                If (lNumber Mod x) = 0 Then Exit Function
            Next
            Check_Prime_Number = True
        End If
    End If
End Function

• Karcrack: 1320ms
• Cobein: 1330ms
• Psyke: 2360ms

Private Function CheckPrimality(ByVal lNum As Long) As Boolean
    Dim i       As Long
 
    If lNum < 10 Then
        If lNum = 2 Then CheckPrimality = True: Exit Function
        If lNum = 5 Then CheckPrimality = True: Exit Function
        If lNum = 1 Then Exit Function
    End If
 
    If Not (lNum And 1) = 1 Then Exit Function
    If (lNum And 5) = 5 Then Exit Function
    For i = 3 To Sqr(lNum) Step 2
        If lNum Mod i = 0 Then Exit Function
    Next
    CheckPrimality = True
End Function

Public Function IsItPrime(ByVal lNumber As Long) As Boolean
    Dim i       As Long
 
    If lNumber < 10 Then
        If lNumber = 2 Then IsItPrime = True: Exit Function
        If lNumber = 5 Then IsItPrime = True: Exit Function
        If lNumber = 1 Then Exit Function
    ElseIf (lNumber And 1) Then
        Select Case (lNumber Mod 10)
            Case 1, 3, 7, 9
                For i = 3 To Sqr(lNumber) Step 2
                    If (lNumber Mod i) = 0 Then Exit Function
                Next i
                IsItPrime = True
        End Select
    End If
End Function