Private
SUB LLSTART_LINKCLICKED
BYVAL Sender
As system.object,
ByVal E
AS
_
System.windows.Forms.LinkLabellinkClickedEventArgs_
Handles llstart.linkClicked
IF isnumeric (me.txtmaxnbr.text) =
False
THEN
Msgbox ("Max Nbr Must Be Numeric!", _
MsgboxStyle.exclamation, _
"Max Nbr Not Numeric")
Return
End
IF
DIM N, I, J N = CINT (Me.txtMaxnbr.Text) DIM Z (N) DIM STARTTIME AS dateTime = now
'INITIALIZE ARRAY for i = 0 to N z (i) = 0 Next
'Mark Multiples of i
For i = 2 to n / 2 for j = 2 * i to n Step i z (j) = 1 Next Next
'Count unmarked Numbers, Which Are Primes Dim NBR = 0
For i = 2 to n if z (i) = 0 THEN NBR = 1 end if Next
DIM TS AS New TimeSpan (now.ticks - starttime.ticks)
Me.lblnBrPrimes.Text = nbr me.lbltime.text = ts.tostring
End Sub Reply: This comilated code has determined my confidence in VB.NET.
For i = 2 to n / 2
For j = 2 * i to n Step i
z (j) = 1
NEXT
NEXT
This algorithm means: traversing 2 to N / 2 Number I, for each I, set all the multiple of 1 in the array z. This z is actually expressed in the BOOL type, 1 is the number, 0 is the number.
For i = 2 to n
IF z (i) = 0 THEN
NBR = 1
END IF
NEXT
Traverse Z, NBR to write down how many prime numbers.
Original algorithm, please see: http://www.math.utah.edu/classes/216/assignment-07.html
This algorithm is indeed very excellent. Its algorithm z (j) = 1 The number of steps to perform the number of steps is x, X is less than N number, it is clear X <= n.
