Compilare: user.cpp: In function ‘void term()’: user.cpp:11:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a.size(); i++) ~~^~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:59:9: warning: unused variable ‘nr_active’ [-Wunused-variable] int nr_active = 0; ^~~~~~~~~ user.cpp:60:12: warning: unused variable ‘s’ [-Wunused-variable] int n, s = 0; ^