Multiplying Int and Char

So, I was going over some old code I wrote about 5 years ago for a project. I decided to copy/paste the old code and update the syntax/formatting and whatnot, since it was coded pretty poorly. Then I got to this line:

sp += sp3.Substring(sp3.Length - 3, 2) + (Convert.ToInt32(Convert.ToChar(sp3.Substring(sp3.Length - 3, 1))) * (Convert.ToChar(sp3.Substring(sp3.Length - 5, 1)))).ToString().Substring(1);

I'm guessing it was a typo, but because I don't really understand what's going on here, I can't seem to get the resulting code to function the same way as the original. Oddly enough, even copy/pasting the old code seems to produce different results. That may be unrelated to this code for all I know, but this was the only thing I could find that struck me as odd.

If you don't see what I'm talking about, it seems as though I omitted the conversion back to an integer on the last bit. Honestly I wasn't even aware you could multiply an integer and char value together, since I haven't started my .NET classes yet. I tried googling it, to no avail; so if anyone could provide some insight, that would be great. Anyway, all of the "sp" variables are string开发者_如何学Cs with a length > 5.

Given that the code was written 5 years ago, you may want to revisit what the purpose of the code is and see if you can write it better. A developer can learn a lot in 5 years.

If you want to better understand what is actually in there, you should break it down into multiple statements and either use the debugger or Console.WriteLine (or Debug.WriteLine) to print out the intermediate values. This way you can see exactly what each step of the line of code does and how it affects the result.

Another helpful way to get more information is using the Visual Studio Debugger: you can highlight part of the line, right click, then click "Add Watch" to have the debugger evaluate just that sub-expression. This will also help you try out different inputs to see how it behaves.

Bonus points for writing unit tests for the different inputs and expected outputs to verify the behavior you are expecting.