字符串转整数字函数

    Function GetInt(ByVal input As String) As Integer
        Dim reg As Regex = New Regex("^\d+$")
        If Not reg.IsMatch(input) Then
            Console.WriteLine("input with invalide charactor")
            Return -1
        End If

        Dim c As Char
        Dim results As Integer = 0
        For Each c In input.ToCharArray()
            results = results * 10
            results = results + Integer.Parse(c)
        Next
        Return results
    End Function