Compilare: main.cpp: In function 'int main()': main.cpp:15:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 15 | for (int i=1;i<str.size()-1;i++) | ~^~~~~~~~~~~~~ main.cpp:35:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 35 | for(int i = 1; i < str.size() - 1; i++){ | ~~^~~~~~~~~~~~~~~~