Compilare: main.cpp: In member function 'void Tree::getTree(Node*&)': main.cpp:28:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 28 | if (ind >= S.size ()) | ~~~~^~~~~~~~~~~~ main.cpp:44:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 44 | while (ind < S.size () && isdigit (S [ind])) | ~~~~^~~~~~~~~~~