c++ - How it should code in OpenCV 2.4 or OpenCV 3.0 -

i want change lines of code original coded in opecv2.3 version

ptr<descriptorextractor > extractor(new surfdescriptorextractor());//  extractor;         new opponentcolordescriptorextractor(             ptr<descriptorextractor>(new siftdescriptorextractor())             )         );  

convert opencv2.4 or opencv3.0.

is understand how should code ? appreciated if can share guide. thanks