Compilare: user.cpp: In function ‘void addword(trie*, std::string, int)’: user.cpp:36:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (r == wd.length()) { nod->word++; return;} ^ user.cpp: In function ‘int delword(trie*, std::string, int)’: user.cpp:48:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (r == wd.length() ) nod->word--; ^ user.cpp: In function ‘int nword(trie*, std::string, int)’: user.cpp:62:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (r == wd.length()) {cout << "prev word : " << wd[r-1] << "\n"; return nod->word; } ^ user.cpp: In function ‘int npref(trie*, std::string, int, int)’: user.cpp:73:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ((r == wd.length() )|| (nod->edge[wd[r] - 'a'] == 0)) ^