Add a pair of C++ books

free-programming-books.md

@@ -452,6 +452,8 @@
 * [C++ Succinctly, Syncfusion ](http://www.syncfusion.com/resources/techportal/ebooks/cplusplus) (PDF, Kindle) *(Just fill the fields with any values)*
 * [Learn C++.](http://www.learncpp.com/) (PDF, Online)
 * [Software Design Using C++](http://cis.stvincent.edu/html/tutorials/swd/) - Br. David Carlson and Br. Isidore Minerd
+* [Introduction to Design Patterns in C++ with Qt](http://ptgmedia.pearsoncmg.com/images/9780131879058/downloads/0131879057_Ezust_book.pdf)
+* [Data Structures and Algorithms with Object-Oriented Design Patterns in C++](http://www.brpreiss.com/books/opus4/index.html)
 
 
 ###Clojure