Compilare: user.cpp: In function ‘int main()’: user.cpp:63:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=n;i++) ^ user.cpp:73:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=n;i++){ ^ user.cpp: In function ‘bool comparator(const str&, const str&)’: user.cpp:56:1: warning: control reaches end of non-void function [-Wreturn-type] } ^