Compilare: user.cpp: In member function ‘void Trie::insert(std::string&, int, int&)’: user.cpp:24:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (pos == s.size()) { ^ user.cpp: In function ‘void BFS(Trie*)’: user.cpp:42:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (start < Q.size()) { ^ user.cpp: In function ‘int main()’: user.cpp:90:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < strlen(text); i++) { ^ user.cpp:100:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < result.size(); i++) ^ user.cpp:69:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("virus.in", "r", stdin); ^ user.cpp:70:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("virus.out", "w", stdout); ^ user.cpp:73:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &N, &M); ^ user.cpp:74:31: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(text, 100002, stdin); ^ user.cpp:80:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &x); ^ user.cpp:81:33: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(word, 1002, stdin); ^