View Compilation Error

0_0_17908303_24785.cpp:2:1: error: 'queue' does not name a type
 queue<Pos> Q;
 ^
0_0_17908303_24785.cpp:6:10: error: variable or field 'bfs' declared void
 void bfs(Pos x)
          ^
0_0_17908303_24785.cpp:6:10: error: 'Pos' was not declared in this scope