Compilare: user.cpp: In member function ‘void Trie::insertWord(std::string)’: user.cpp:45:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int index = 0; index < word.length(); index++ ){ ^ user.cpp:55:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ( index == word.length()-1 ) ^ user.cpp: In member function ‘void Trie::deleteWord(std::string)’: user.cpp:66:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int index = 0; index < word.length(); index++ ){ ^ user.cpp:76:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ( index == word.length()-1 ){ ^ user.cpp: In member function ‘int Trie::spottedWords(std::string)’: user.cpp:88:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int index = 0; index < word.length(); index++ ){ ^ user.cpp: In member function ‘int Trie::prefixLength(std::string)’: user.cpp:103:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int index = 0; index < word.length(); index++ ){ ^