Compilare: user.cpp: In function ‘void add(Trie*, std::string, int)’: user.cpp:27: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void remove(Trie*, std::string, int)’: user.cpp:45: warning: comparison between signed and unsigned integer expressions user.cpp:49: warning: array subscript has type ‘char’ user.cpp:50: warning: array subscript has type ‘char’ user.cpp:50: warning: array subscript has type ‘char’ user.cpp:52: warning: array subscript has type ‘char’ user.cpp:53: warning: array subscript has type ‘char’ user.cpp: In function ‘void print(Trie*, std::string, int)’: user.cpp:64: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void max_prefix(Trie*, std::string, int)’: user.cpp:84: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:120: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:121: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result