Compilare: main.cpp: In member function 'bool nr::operator<(const nr&) const': main.cpp:36:16: warning: statement has no effect [-Wunused-value] f3 < that.f3; ~~~^~~~~~~~~ main.cpp: In function 'int main()': main.cpp:48:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v.size(); ++i) ~~^~~~~~~~~~ main.cpp:57:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v.size() - 1; ++i) ~~^~~~~~~~~~~~~~