程序设计:求小于一个数(18000)的素数

private Sub C1 _ Click()
a % = 18000
Do
a % = a %-1
循环，直到I prime(a %)
text 1。text = a %
结束Sub

Private Sub C2_Click()
打开“out5.txt”作为#1输出
Print #1，Text1。Text
关闭# 1
结束Sub

私有函数is prime(a As Integer)As Boolean
Dim flag As Boolean
flag = True
b % = 2
Do While b % If Int(a/b %)= a/b % Then
flag = False
Else
b % = b %+1
End If
Loop
is prime = flag
End函数