Programming Forums > Application Development > Visual Basic .NET

Intimidat0r · Jul 8th, 2005, 4:03 PM

I have tried to make a program to decrypt simple ROT decryptions which is where if it's like ROT 4 you move each letter 4 spaces down, so A becomes E, W becomes Z and so on. Here is my code:

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    Dim ROTIndex As Integer
    Dim Encrypted As String
    Dim Decrypted() As String = ""

    Sub Main()
        Console.WriteLine("Rotation index: ")
        ROTIndex = Console.ReadLine()
        Console.WriteLine("Encrypted text: ")
        Encrypted = Console.ReadLine()
        For Index As Integer = 0 To Encrypted.Length
            Decrypted = Decrypted & Chr(Asc(Encrypted.Substring(Index, 1) + 13))
        Next
        Console.WriteLine("Decrypted Text: " & Decrypted)
    End Sub

It looks all well and good but when I try to run it I get a bug saying "Invalid cast exception -> cast from string "h" to type 'Double' is not valid" and it says it's occurring on the line that says this:

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Decrypted = Decrypted & Chr(Asc(Encrypted.Substring(Index, 1) + 13))

Does anybody know why it may be doing this?

Jul 8th, 2005, 4:03 PM	#1
Intimidat0r Hobbyist Programmer Join Date: May 2005 Location: Don't know, but the padded walls are a nice touch. Posts: 126 Rep Power: 0	ROT Decryptor I have tried to make a program to decrypt simple ROT decryptions which is where if it's like ROT 4 you move each letter 4 spaces down, so A becomes E, W becomes Z and so on. Here is my code: (Toggle Plain Text) Dim ROTIndex As Integer Dim Encrypted As String Dim Decrypted() As String = "" Sub Main() Console.WriteLine("Rotation index: ") ROTIndex = Console.ReadLine() Console.WriteLine("Encrypted text: ") Encrypted = Console.ReadLine() For Index As Integer = 0 To Encrypted.Length Decrypted = Decrypted & Chr(Asc(Encrypted.Substring(Index, 1) + 13)) Next Console.WriteLine("Decrypted Text: " & Decrypted) End Sub Dim ROTIndex As Integer Dim Encrypted As String Dim Decrypted() As String = "" Sub Main() Console.WriteLine("Rotation index: ") ROTIndex = Console.ReadLine() Console.WriteLine("Encrypted text: ") Encrypted = Console.ReadLine() For Index As Integer = 0 To Encrypted.Length Decrypted = Decrypted & Chr(Asc(Encrypted.Substring(Index, 1) + 13)) Next Console.WriteLine("Decrypted Text: " & Decrypted) End Sub It looks all well and good but when I try to run it I get a bug saying "Invalid cast exception -> cast from string "h" to type 'Double' is not valid" and it says it's occurring on the line that says this: (Toggle Plain Text) Decrypted = Decrypted & Chr(Asc(Encrypted.Substring(Index, 1) + 13)) Decrypted = Decrypted & Chr(Asc(Encrypted.Substring(Index, 1) + 13)) Does anybody know why it may be doing this? __________________ Children in the dark cause accidents, and accidents in the dark cause children. http://www.ronincoders.org

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Programming Forums > Application Development > Visual Basic .NET

ROT Decryptor