What is the meaning of the decision tree algorithm name "c4.5"?

Question

I'm learning Machine Learning. In this subject, I see a decision tree name "c4.5" but I do not know "c4.5" stand for what. Is there anyone help me? I search about it a lots but I still do not have the answer :D

Answer 1

In the book "C4.5: Programs for Machine Learning" by Quinlan I wasn't able to quickly find an description of why that name was chosen (it's about 300 pages including appendices with lots of source code though, so didn't read all that).

The story I heard is that the "C" simply indicates that the algorithm was implemented in C, and that Quinlan was maybe very proud of the fact that he was able to program in C. Then I suppose the "4.5" is simply a version number of the software.

Note that a Java implementation of the same / a similar algorithm in Weka is named "J48".