Compilare: user.cpp: In function ‘void addWord(Node*, std::string&, int)’: user.cpp:29:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (pos == w.size() - 1) { ^ user.cpp: In function ‘int countWords(Node*, std::string&, int)’: user.cpp:40:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (pos == w.size() - 1) return v -> words; ^ user.cpp: In function ‘void deleteWord(Node*, std::string&, int)’: user.cpp:47:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (pos == w.size() - 1) { ^ user.cpp: In function ‘int longestPrefix(Node*, std::string&)’: user.cpp:67:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (++pos >= w.size()) break; ^