A implementation of the back propagation algorithm in c++. The implementation is based on a blog post [1] by James McCaffrey. In order to make this code more scalable, I made several changes:

(1) separate the bp algorithm from the network structure. (2) separate the activation function from the bp algorithm. (3) add normalization method for traning and testing data.

[1] Neural Network Back-Propagation for Programmers: http://msdn.microsoft.com/en-us/magazine/jj658979.aspx