Compilare: main.cpp: In function 'void sterge(nod*, std::string, int)': main.cpp:24:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 24 | if(k<str.size()) | ~^~~~~~~~~~~ main.cpp: In function 'int getpref(nod*, std::string, int)': main.cpp:51:13: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 51 | if(pref == str.size() || q->urm[str[pref]-'a'] == NULL) return pref; | ~~~~~^~~~~~~~~~~~~