Deleting elements from a vector

Question

The following C++ code fills a vector with a number of objects and then removes some of these objects, but it looks like it deletes the wrong ones:

vector

        

Answer 1

the elegant way would be:

std::vector photons = source->emitPhotons();
photons.erase(
      std::remove_if(photons.begin(), photons.end(), isUseless),
      photons.end());

and:

bool isUseless(const Photon& photon) { /* whatever */ }