Compilare: user.cpp: In function ‘int main()’: user.cpp:36:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < primes.size(); i++) { ^ user.cpp:44:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = sz; j < v.size(); j += 2 * sz) ^ user.cpp:49:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v.size(); i++) ^