vb.net求回文数 vb返回数组长度

VB 回文数

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)。

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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

VB.NET 编程 关于回文数的题目。

在WinForm项目的窗体上添加一个按钮和文本框，然后把下面的代码粘贴上去就可以了。

Public Function lsH(ByVal n As String) As String

Dim s1 As String = ""

Dim s2 As String = ""

Dim i As Integer = 0

Dim j As Integer

If n.Length = 1 Then

Return ("是回文数")

Else

If Tell_JiOu(n.Length) = 1 Then

j = (n.Length + 1) / 2

s1 = Mid(n, 1, j)

Else

j = n.Length / 2 + 1

s1 = Mid(n, 1, j - 1)

End If

For i = n.Length To j Step -1

s2 = s2 + Mid(n, i, 1)

Next

If s1 = s2 Then

Return "是回文数"

Else

Return "不是回文数"

End If

End If

End Function

'判断一个整数的奇偶

Public Function Tell_JiOu(ByVal k As Integer) As Integer

If k Mod 2 = 0 Then

Return 2

Else

Return 1

End If

End Function

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles Button1.Click

Button.Text = lsH(TextBox1.Text)

End Sub

VB.NET 编写函数过程IsH(n) 判断是否为回文数

你的i = Len(Str(a))会出问题。

If i 1 Then

Return True

End If

这个返回在if内部，当条件不满足将导致函数无返回。

以下代码仅供参考:

Function IsH(ByVal a As Long) As Boolean

Dim i As Long, j As Long, t As String

t = a.ToString

i = t.Length

Select Case i

Case 1

Return True

Case 2

If Mid(t, 1, 1) = Mid(t, 2, 1) Then Return True Else Return False

Case 3

If Mid(t, 1, 1) = Mid(t, 3, 1) Then Return True Else Return False

Case Else

For j = 1 To i \ 2

If Mid(t, j, 1) Mid(t, i - j + 1, 1) Then Return False

Next j

End Select

Return True

End Function

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