View Compilation Error

0_0_23202598_9609.cpp: In function 'void BFS(P)':
0_0_23202598_9609.cpp:58:2: error: missing template arguments before 'Q'
  Q;
  ^
0_0_23202598_9609.cpp:61:5: error: 'Q' was not declared in this scope
     Q.push(node);
     ^