在VB程序中输出对称数,可以通过以下几种方法实现:
方法一:检查数字是否为回文
可以通过编写一个函数来检查一个数字是否为回文,然后输出所有满足条件的数字。
```vb
Private Function IsPalindrome(ByVal number As Integer) As Boolean
Dim reversed As String = New String(number.ToString().ToCharArray().Reverse())
Return number.ToString() = reversed
End Function
Private Sub Command1_Click()
Dim i As Integer
For i = 1 To 999
If IsPalindrome(i) Then
Print i
End If
Next
End Sub
```
方法二:生成对称数
可以编写一个程序生成对称数,例如输出形式为“1 3 …… n-2 n n-2 3 1”的对称数字串。
```vb
Private Sub Command1_Click()
Dim n As Integer
Dim i As Integer
Dim s As String
n = Text1.Text
s = ""
For i = 1 To n \ 2 + 1
s = s & i
Next
For i = 1 To n \ 2
s = s & n - i + 1
Next
s = s & s.Substring(0, s.Length - 1)
Text2.Text = s
End Sub
```
方法三:输出对称数序列
可以编写一个程序输出对称数序列,例如输出1到n的所有对称数。
```vb
Private Sub Command1_Click()
Dim n As Integer
Dim i As Integer
Dim s As String
n = Text1.Text
s = ""
For i = 1 To n \ 2 + 1
s = s & i
Next
For i = 1 To n \ 2
s = s & n - i + 1
Next
s = s & s.Substring(0, s.Length - 1)
Text2.Text = s
End Sub
```
方法四:输出对称数对
可以编写一个程序输出对称数对,例如输出所有形如i和n+2013-i的对称数。
```vb
Private Sub Command1_Click()
Dim i As Integer
For i = 1 To 999
If IsPalindrome(i + 2013) Then
Print i
End If
Next
End Sub
```
方法五:输出对称数三元组
可以编写一个程序输出对称数三元组,例如输出所有形如(i, j, k)的对称数,其中i + j + k = n且i <= j <= k。
```vb
Private Sub Command1_Click()
Dim n As Integer
Dim i As Integer
Dim j As Integer
Dim k As Integer
n = Text1.Text
For i = 1 To n \ 3 + 1
For j = i To n \ 2 - i + 1
k = n - i - j
If i <= j And j <= k And IsPalindrome(i + 2013) And IsPalindrome(j + 2013) And IsPalindrome(k + 2013) Then
Print i, j, k
End If
Next j
Next i
End Sub
```
这些方法可以根据具体需求选择使用,以实现对称数的输出。