View Compilation Error

0_0_33092742_27770.cpp:11:27: error: array must be initialized with a brace-enclosed initializer
  int tree[maxn][26] = { 0 };
                           ^
0_0_33092742_27770.cpp: In member function 'void ACmechine::init()':
0_0_33092742_27770.cpp:17:31: error: 'memset' was not declared in this scope
   memset(tree, 0, sizeof(tree));
                               ^
0_0_33092742_27770.cpp: In member function 'void ACmechine::insertworld(char*)':
0_0_33092742_27770.cpp:25:31: error: 'strlen' was not declared in this scope
   for (int i = 0; i < strlen(s); i++)
                               ^
0_0_33092742_27770.cpp: In member function 'int ACmechine::query(char*)':
0_0_33092742_27770.cpp:66:31: error: 'strlen' was not declared in this scope
   for (int i = 0; i < strlen(s); i++)
                               ^