Alycus Alycus - 6 months ago 18x Question

C# Code generator with vowels and consonants, vowels not showing up

I have a random key generator in C# that's supposed to generate a key in the following format:

consonant + vowel + consonant + vowel + four numerical digits

So for example it would be BABA1234 or ZUZU9876.

Currently, however, the vowels don't show up, though everything else does, so I end up getting output like B_B_1234, for example, where the underscores represent either spaces or unrecognized character boxes.

I've been looking through some examples such as this, this and this, but I still haven't gotten it to work. The C# code is as follows:

public static string shortText()
string randomNumber = new Random().Next(1000, 9999).ToString();
char c1 = consonant();
char c2 = vowel();
char c3 = consonant();
char c4 = vowel();

return string.Format("{0}{1}{2}{3}{4}", c1, c2, c3, c4, randomNumber);

private static char vowel()
int selected = new Random().Next(0, 4);
List<int> list = new List<int> { 65, 69, 73, 79, 85 };

return Strings.Chr(selected);

private static char consonant()
int selected = new Random().Next(65, 90);
List<int> list = new List<int> { 65, 69, 73, 79, 85 };

if (list.Contains(selected) == false)
return Strings.Chr(selected);
else {
return Strings.Chr(selected + 1);

An additional note is that this code was originally written in VB (which is why there is a Strings.Chr in the C# code above, I added a reference to the VB library), where it worked correctly and generated codes according to the format in the beginning. I converted it over to C# and edited it slightly to remove the errors, but it looks like the conversion hasn't been perfect. Here is the VB code:

Public Class Form1
Private Sub btnGenerateKey_Click(sender As Object, e As EventArgs) Handles btnGenerateKey.Click
txtKey.Text = shortText()
End Sub

Private Shared Function shortText() As String
Dim randomNumber As String = New Random().Next(1000, 9999).ToString
Dim c1 As Char = consonant()
Dim c2 As Char = vowel()
Dim c3 As Char = consonant()
Dim c4 As Char = vowel()

Return String.Format("{0}{1}{2}{3}{4}", c1, c2, c3, c4, randomNumber)
End Function

Private Shared Function vowel() As Char
Dim list As List(Of Integer) = New List(Of Integer)({65, 69, 73, 79, 85})

Return Chr(list(New Random().Next(0, 4)))
End Function

Private Shared Function consonant() As Char
Dim selected As Integer = New Random().Next(65, 90)
Dim list As List(Of Integer) = New List(Of Integer)({65, 69, 73, 79, 85})

If list.Contains(selected) = False Then
Return Chr(selected)
Return Chr(selected + 1)
End If
End Function
End Class

Any help is much appreciated.


vowel() is returning the value of the random number (i.e. 1-4), not an element from your vowel list.

Fix it by changing

return Strings.Chr(selected);


return Strings.Chr(list[selected]);

Additional problems

There are a couple of other problems with your code though.

1) You are not using Random correctly. Don't create a new Random instance each time you need a random number - create one instance and use it for all requests for a random number.

2) You are more likely to get the consonants 'b', 'f', 'j', 'p', 'v', due to your algorithm. Instead of taking the next letter if you get a vowel inside consonant(), you should just have a list of 21 chars, and grab a random entry from that list.

3) Why are you creating a list of ints to store your consonants? Why not create a list of chars and avoid casting. Doing it this way would have made your actual bug immediately obvious, as you would have got a compile error :)