Compilare: main.cpp: In member function 'bool elem::operator<(const elem&) const': main.cpp:12:28: warning: comparison of integer expressions of different signedness: 'int' and 'const long unsigned int' [-Wsign-compare] 12 | for(int index = 0; index < std::min(str.size(), nr2.str.size()); index++){ | ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:29:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 29 | for(int index = 0; index < sortstr.size(); index++){ | ~~~~~~^~~~~~~~~~~~~~~~