Compilare: main.cpp: In function 'bool cmp(std::__cxx11::string, std::__cxx11::string)': main.cpp:55:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < a.size(); i++) { ~~^~~~~~~~~~ main.cpp:59:1: warning: control reaches end of non-void function [-Wreturn-type] } ^