View Compilation Error

0_0_35162832_9046.cpp: In function 'void bfs(Pos)':
0_0_35162832_9046.cpp:61:34: error: 'memset' was not declared in this scope
     memset(step, -1, sizeof(step));
                                  ^
0_0_35162832_9046.cpp: In function 'int main()':
0_0_35162832_9046.cpp:108:39: error: 'memset' was not declared in this scope
         memset(block, 0, sizeof(block));
                                       ^