View Compilation Error

0_0_19461610_20747.cpp: In member function 'void ACAutomaton::reset()':
0_0_19461610_20747.cpp:27:44: error: 'memset' was not declared in this scope
         memset(trie[0], -1, sizeof(trie[0]));
                                            ^
0_0_19461610_20747.cpp: In member function 'void ACAutomaton::add(char*)':
0_0_19461610_20747.cpp:41:51: error: 'memset' was not declared in this scope
                 memset(trie[n],-1, sizeof(trie[n]));
                                                   ^