Writing a base conversion tool and having trouble with hexadecimal

Question

My current assignment is to write a converter to different systems. Converting to binary was no problem, but I am having some troubles with hexadecimal. Here is my code:

    public string[] ConvertInput(int pInput, int pBase)
    {
        List<string> Output = new List<string>();
        int Tmp = pInput;
        int TmpBin;

        for (int i = 0; Tmp > 0; i++)
        {
            TmpBin = Tmp % pBase;
            Tmp = Tmp / pBase;
            if (TmpBin >= 10)
            {
                char c = (char)TmpBin;
                Output.Add(c.ToString());
            }
            else
            {
                Output.Add(TmpBin.ToString()); 
            }
        }

        string[] OutArray = Output.ToArray();

        Array.Reverse(OutArray);

        return OutArray;
    }

So if I try to convert the number 15555 to hexadecimal, it should give 3cc3 back, but what it does is return 3\f\f3.

What did I do wrong?

You're casting binary values to char - you aren't converting the binary values to characters in the range 'A' to 'F' correctly. — Matthew Watson, Aug 22 '16 at 14:45
BTW, you can get rid of the array of strings approach and just do it all in one string. You'll need a Reverse of string method, though. See http://stackoverflow.com/a/228060/49251. So you can do it with output declard `string Output = ""`. Then you add to it via `Output += c.ToString();`, etc. Then referse the string and have the method return a string. — DWright, Aug 22 '16 at 15:25
@Raphnika: I see you edited your question to re-include the "thanks" at the end -- the general consensus around here is to omit any kind of "thanks" from your posts. Think of questions and answers here as technical writing -- while it may seem harsh, there's just no point. Thank your answerer(s) by accepting or upvoting when appropriate. — Cᴏʀʏ, Aug 22 '16 at 15:39

score 2 · Accepted Answer · answered Aug 22 '16 at 14:48

2

Instead of this:

if (TmpBin >= 10)
{
    char c = (char)TmpBin;
    Output.Add(c.ToString());
}

Do this:

if (TmpBin >= 10)
{
    char c = (char)('A' + (TmpBin - 10));
    Output.Add(c.ToString());
}

In your version, you are casting the decimal values 10, 11, 12 etc directly to characters, and (for example) the character with code 10 is line feed, not 'A'.

answered Aug 22 '16 at 14:48

Matthew Watson

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10
158
276

Allright! Got it. Thank you very much for your help and have a nice day! – Raphnika Aug 22 '16 at 14:53
1

I know this was an assignment, but in an actual .NET production application, you could and should replace your entire method with `15555.ToString("X");`. You wouldn't want to recreate the wheel, though your professor probably wants to you to do it the hard way. – Cᴏʀʏ Aug 22 '16 at 14:59
@Cory yeah... he wants us to understand how everything works. – Raphnika Aug 22 '16 at 15:04

Writing a base conversion tool and having trouble with hexadecimal

1 Answers1