vb.net - 如何创建未定义的循环计数

Question

我正在尝试创建一个程序，它将循环遍历所有字母。

我想例如显示 aaaa，然后 aaab 到 aaaz，然后 aaba 等等到 zzzz。

问题是:如何让用户输入字母数？

这是我只有 3 个字母的代码:

Dim abc() As String = {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", _
    "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"}
Console.ReadLine()
Dim indx As Integer = 0
For a = 0 To 25
    For b = 0 To 25
         For c = 0 To 25
              Console.WriteLine("{0}{1}{2}", abc(a), abc(b), abc(c))           
         Next
    Next
Next

Answer 1

递归是您在这里寻找的工具。你想重复到一定深度；该深度是用户的输入。在这个例子中，我提供了 3 的深度(意思是所有三个字母的排列，正如你在你的问题中所描述的那样)。您可以将值更改为您希望的任何值，或者更好的是读取用户的输入。

Dim abc() As String = {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"}

Sub Main()
    Dim depth As Integer
    depth = 3
    IterateAlphabet("", depth)
    Console.ReadKey()

End Sub

Sub IterateAlphabet(ByVal currentLetters As String, ByVal currentDepth As Integer)
    For letter = 0 To 25
        Dim newLetters As String
        newLetters = currentLetters + abc(letter)
        If (currentDepth = 1) Then
            Console.WriteLine("{0}", newLetters)
        Else
            IterateAlphabet(newLetters, currentDepth - 1)
        End If
    Next

End Sub