View Compilation Error

0_0_23963586_20109.cpp: In function 'int BFS(int)':
0_0_23963586_20109.cpp:10:28: error: 'memset' was not declared in this scope
  memset(pre, 0, sizeof(pre));
                            ^
0_0_23963586_20109.cpp: In function 'int main()':
0_0_23963586_20109.cpp:38:29: error: 'memset' was not declared in this scope
   memset(map, 0, sizeof(map));
                             ^