C++ is a superset of only a subset of C

C and C++ are two very interlaced, but still distinct languages. Believe it or not, there were already tiny divergences even at the very birth of C++. Yet many developers fall into the trap of thinking of C++ as a perfect superset over C, what then leads to unpleasant surprise when something differs. Thus below I list few online resources where one may learn a bit on the topic.