Compilare: user.cpp: In function ‘void add(Trie*, int, std::string&)’: user.cpp:18: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int find(Trie*, int, std::string&)’: user.cpp:30: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘bool remove(Trie*, int, std::string&)’: user.cpp:40: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int prefix(Trie*, int, std::string&)’: user.cpp:56: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:64: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:65: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:70: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result