View Compilation Error

0_0_13900034_27980.cpp: In function 'int bfs(int, bool)':
0_0_13900034_27980.cpp:15:24: error: 'memset' was not declared in this scope
  memset(in,0,sizeof(in));
                        ^
0_0_13900034_27980.cpp: In function 'int main()':
0_0_13900034_27980.cpp:49:29: error: 'memset' was not declared in this scope
         memset(x,0,sizeof(x));
                             ^