如何产生不重复的随机数？

时　间:2008-09-06 08:08:59
作　者:fan0217   ID：3202  城市：绵阳
摘　要:如何产生不重复的随机数？
正　文:

先创建个类模块：Random

类模块代码如下：
CODE:
Dim c As Collection
'初始化，定义产生随机数的最小值和最大值
Public Sub Init(min As Integer, max As Integer)
Set c = New Collection
Dim i As Integer
    For i = min To max
        c.Add i
    Next
End Sub
'产生不重复的随机数
Public Function RandomNext() As Integer
Dim i As Integer
Dim number As Integer, upperbound As Integer
    upperbound = c.Count
    If upperbound > 0 Then
        number = Int((upperbound) * Rnd + 1)
        RandomNext = CInt(c.Item(number))
        c.Remove (number)
    Else
        RandomNext = 0
    End If
End Function
Private Sub Class_Terminate()
    Set c = Nothing
End Sub
测试：
CODE:
Dim r As New Random
 
Sub Test() '请先运行Init
Dim i As Integer
    For i = 0 To 10
       Debug.Print r.RandomNext
    Next
End Sub
Sub Init()
    r.Init 1, 100
End Sub

这里使用集合来实现的，也可以用哈希表来做，道理差不多。哈希表需要自己定义类模块。