View Compilation Error

0_0_33823817_8533.cpp: In function 'void bfs(windows*)':
0_0_33823817_8533.cpp:24:24: error: 'memset' was not declared in this scope
   memset(r, 0, sizeof r);
                        ^
0_0_33823817_8533.cpp: In function 'int main()':
0_0_33823817_8533.cpp:53:30: error: 'memset' was not declared in this scope
   memset(room, 0, sizeof room);
                              ^