You may also refer to:
http://nbviewer.ipython.org/github/BVLC/caffe/blob/master/examples/net_surgery.ipynb
https://github.com/BVLC/caffe/blob/master/examples/cpp_classification/classification.cpp
http://mochajl.readthedocs.org/en/latest/user-guide/tools/import-caffe-model.html

Comments for errors in the first link
1. ImportError: No module named Image:
Replace “import Image” with “from PIL import Image”
2. matplotlib does not show any image
import matplotlib.pyplot as plt
plt.imshow(im) #doesn’t show any image
plt.show() # Add this in the last line.

 

Dig into C++:
Prerequisites: Google Protobuf.
Key function to read weights from caffemodel file
::google::protobuf::Message::ParseFromCodedStream
Key related class implementation in Caffe
class NetParameter : public ::google::protobuf::Message {
…..
}