prog.cpp:1:6: error: 'trie' has not been declared
 bool trie::exists_key(std::string::const_iterator begin, std::string::const_iterator end, int16_t &value) {
      ^
prog.cpp:1:28: error: 'std::string' has not been declared
 bool trie::exists_key(std::string::const_iterator begin, std::string::const_iterator end, int16_t &value) {
                            ^
prog.cpp:1:63: error: 'std::string' has not been declared
 bool trie::exists_key(std::string::const_iterator begin, std::string::const_iterator end, int16_t &value) {
                                                               ^
prog.cpp:1:91: error: 'int16_t' was not declared in this scope
 bool trie::exists_key(std::string::const_iterator begin, std::string::const_iterator end, int16_t &value) {
                                                                                           ^
prog.cpp:1:100: error: 'value' was not declared in this scope
 bool trie::exists_key(std::string::const_iterator begin, std::string::const_iterator end, int16_t &value) {
                                                                                                    ^
prog.cpp:1:105: error: expression list treated as compound expression in initializer [-fpermissive]
 bool trie::exists_key(std::string::const_iterator begin, std::string::const_iterator end, int16_t &value) {
                                                                                                         ^
prog.cpp:1:107: error: expected ',' or ';' before '{' token
 bool trie::exists_key(std::string::const_iterator begin, std::string::const_iterator end, int16_t &value) {
                                                                                                           ^

Standard output is empty