View Compilation Error

0_0_34780890_16409.cpp: In function 'void bfs()':
0_0_34780890_16409.cpp:21:9: error: 'r' was not declared in this scope
  while(!r.empty())
         ^
0_0_34780890_16409.cpp: In function 'int main()':
0_0_34780890_16409.cpp:80:10: error: too many arguments to function 'void bfs()'
   bfs(a,b);
          ^
0_0_34780890_16409.cpp:19:6: note: declared here
 void bfs()
      ^