Compilare: main.cpp: In function 'std::vector<int> getPrimeFactors(long long int)': main.cpp:45:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0;i < primeNr.size() && primeNr[i] <= b;++i) { ~~^~~~~~~~~~~~~~~~ main.cpp: In function 'void back(int, std::vector<int>&)': main.cpp:57:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = startPos; i < factors.size();i++) { ~~^~~~~~~~~~~~~~~~ main.cpp:63:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(pos < factors.size()) ~~~~^~~~~~~~~~~~~~~~