# Programming Theory

Best practices, structuring of code, dissecting algorithms and talking about the “Why?”

## Rijndael Class Example for File Encryption in C#

Hello readers! It has been awhile since my last post. Lots of things have been going on lately and I have been busy developing some great code for some great people. In this entry I am going to show you a bit of plain text file encryption using the Rijndael Algorithm. This example is a fairly simple one and I hope to explain the basics as I move through an ...

## Playing with Recursive Directory Diving in VB.NET

So recently someone asked about listing files from several directories but only to a given depth. They were using a DirectoryInfo object, as they probably should, to get a list of files. There was a problem with this however since the constructor of this object only offers a version where you specify no recursion on the sub directories or full recursion and get all the sub directories. This is an ...

## Reflective N-bit Binary Gray Code Using Ruby

So what is behind the theory of binary gray code? It was named after Frank Gray and is a numerical system where each successive value differs from the one before it by one bit value. It is like counting in binary, but in binary counting a step may require changing two bits. For instance going from 1 (01) to 2 (10) would involve changing the most significant value 1 ...

## Intersection of LinkedLists Using Java

Yesterday a user came through the Java forum looking for help with finding the intersection of two LinkedList sets. If you were anything like I was in school, you probably had a flash back to math class and the teacher drawing Venn Diagrams up on the white board. Two circles, usually representing two sets of elements, and where they overlapped was elements shared between the sets. Maybe they even drew ...

## Histogram Equalization Using PHP

The other day someone on the board had asked about histogram equalization and it had sparked some thoughts about how it is applied to picture correction and enhancement. Then of course it hit me like a ton of bricks (ouch!), why not make this into a blog post? So here I am telling all you fine people about using PHP to equalize the histogram information in pictures. Now we all ...

## Slot Machine Example in C++

I was bored and that can be a dangerous thing. Like doodling on the phone book while you are talking on the phone, I doodle code while answering questions on DIC. Yeah, it means I have no life and yes it means I was born a coder. During this little doodle I decided to make a slot machine. But not your standard slot machine per say, but one designed a ...