Compilare: main.cpp: In function 'int main()': main.cpp:59:34: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 59 | for (int i = a.size(); i < b.size(); i++) { | ~~^~~~~~~~~~