Compilare: user.cpp: In function ‘int main()’: user.cpp:29:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < c.length(); ++j){ ~~^~~~~~~~~~~~ user.cpp:41:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(vf+1 != q.size()){ ~~~~~^~~~~~~~~~~ user.cpp:56:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < r.length(); ++i){ ~~^~~~~~~~~~~~