轉發的：

Private Function min(one As Integer, two As Integer, three As Integer)
min = one
If (two < min) Then
min = two
End If
If (three < min) Then
min = three
End If
End Function

Private Function ld(str1 As String, str2 As String)
Dim n, m, i, j As Integer
Dim ch1, ch2 As String
n = Len(str1)
m = Len(str2)
Dim temp As Integer
If (n = 0) Then
ld = m
End If
If (m = 0) Then
ld = n
End If
Dim d As Variant
ReDim d(n + 1, m + 1) As Variant
For i = 0 To n
d(i, 0) = i
Next i
For j = 0 To m
d(0, j) = j
Next j
For i = 1 To n
ch1 = Mid(str1, i, 1)
For j = 1 To m
ch2 = Mid(str2, j, 1)
If (ch1 = ch2) Then
temp = 0
Else
temp = 1
End If
d(i, j) = min(d(i - 1, j) + 1, d(i, j - 1) + 1, d(i - 1, j - 1) + temp)
Next j
Next i
ld = d(n, m)
End Function

Public Function sim(str1 As String, str2 As String)
Dim ldint As Integer
ldint = ld(str1, str2)
Dim strlen As Integer
If (Len(str1) >= Len(str2)) Then
strlen = Len(str1)
Else
strlen = Len(str2)
End If
sim = 1 - ldint / strlen
End Function

Sub test()
Dim s1 As String
Dim s2 As String
s1 = Range("c2")
s2 = Range("c4")
MsgBox sim(s1, s2)

End Sub