vb 编程，回文

Function IsH(n) As Boolean

Dim s As String

s = CStr(n)

IsH = s = StrReverse(s)

End Function

Function IsH2(n) As Boolean 'Mid版

Dim s As String, i As Integer, k As Integer, rt As Boolean

s = CStr(n)

k = Len(s) \ 2

rt = True

For i = 1 To k

If Mid(s,i,1)<>Mid(s,k-i+1,1) = False Then

rt = False

Exit For

End If

Next

IsH2 = rt

End Function

在数学中也有这样一类数字有这样的特征，成为回文数(palindrome number)。

设n是一任意自然数。若将n的各位数字反向排列所得自然数n1与n相等，则称n为一回文数。例如，若n=1234321，则称n为一回文数但若n=1234567，则n不是回文数。

注意:

1.偶数个的数字也有回文数124421

如：1234321

Len(s) / 2=7/2=3.5

k = 1，Mid(s, k, 1)=1，Mid(s, (Len(s) - k + 1), 1)=Mid(s, (7 -1 + 1), 1)=1

k = 2，Mid(s, k, 1)=2，Mid(s, (Len(s) - k + 1), 1)=Mid(s, (7 -2 + 1), 1)=2

……

如果k = 3，为假，就退出循环，

If k >Len(s) / 2 Then

k=3<Len(s) / 2 =3.5

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