Compilare: main.cpp: In function 'void insert(TrieNode*, const std::string&, int)': main.cpp:14:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 14 | if (index==word.length()) | ~~~~~^~~~~~~~~~~~~~~ main.cpp: In function 'void remove(TrieNode*, const std::string&, int)': main.cpp:29:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 29 | if (index==word.length()) | ~~~~~^~~~~~~~~~~~~~~ main.cpp: In function 'int frequency(TrieNode*, const std::string&, int)': main.cpp:43:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 43 | if (index==word.length()) | ~~~~~^~~~~~~~~~~~~~~