程序設(shè)計(jì):求小于一個(gè)數(shù)(18000)的素?cái)?shù)

Private Sub C1_Click()
     a% = 18000
     Do
     a% = a% - 1
     Loop Until isprime(a%)
     Text1.Text = a%
    End Sub
    Private Sub C2_Click()
     Open "out5.txt" For Output As #1
     Print #1, Text1.Text
     Close #1
    End Sub
    Private Function isprime(a As Integer) As Boolean
     Dim flag As Boolean
     flag = True
     b% = 2
     Do While b% <= Int(a / 2) And flag
     If Int(a / b%) = a / b% Then
     flag = False
     Else
     b% = b% + 1
     End If
     Loop
     isprime = flag
    End Function