Compilare: user.cpp: In function ‘void adauga(std::string)’: user.cpp:32:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < x.size() - 1; i++) { ^ user.cpp: In function ‘void sterge(std::string)’: user.cpp:53:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < x.size() - 1; i++) { ^ user.cpp: In function ‘int nr_aparitii(std::string)’: user.cpp:65:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < x.size(); i++) { ^ user.cpp: In function ‘int prefix(std::string)’: user.cpp:76:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 1; i < x.size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:84:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trie.in", "r", stdin); ^ user.cpp:85:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trie.out", "w", stdout); ^