String Toolkit for Text Processing

Link: http://www.codeproject.com/Articles/23198/C-String-Toolkit-StrTk-Tokenizer

It can be used as lite version of Boost.

Open-source implementation of Boostexter

Link: http://code.google.com/p/icsiboost/

Intro: Boosting is a meta-learning approach that aims at combining an ensemble of weak classifiers to form a strong classifier. Adaptive Boosting (Adaboost) is a greedy search for a linear combination of classifiers by overweighting the examples that are misclassified by each classifier. icsiboost implements Adaboost over stumps (one-level decision trees) on discrete and continuous attributes (words and real values)