Hi prasun,
It will be a great help, if some body can suggest me the part of the program to be used as I am getting confused while selecting the .cpp and .h files.
The header is cctbx/uctbx.h and the implementation is in cctbx/uctbx/uctbx.cpp. If you develop with C++, you need to pass -I/path/to/cctbx_sources where cctbx_sources is the directory that contains all the sources (i.e. cctbx, mmtbx, scitbx, etc are direct subdirectories of it). Having hopefully answered your question, a word of advice: the cctbx is designed to be used from Python. Only the very basic features are available in C++. And many features are much easier to use from Python than from C++. It all depends on what you wish to achieve of course but since you are at the beginning of your project, I thought it would be the right time to think about the programming language. Best wishes, Luc Bourhis