Compilare: user.cpp: In function ‘int main()’: user.cpp:31:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (q.size () > u){ ~~~~~~~~~~^~~ user.cpp:36:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (q.size() > l && q.front () < 0){ ~~~~~~~~~^~~ user.cpp:41:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (s[i-l] < 0 && q.size() > l){ ~~~~~~~~~^~~ user.cpp:43:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (q.size() > l){ ~~~~~~~~~^~~