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)': main.cpp:51:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 51 | for(int i=0; i<str.size(); i++) | ~^~~~~~~~~~~