View Compilation Error

0_0_10822046_4111.cpp: In function `int bfs()':
0_0_10822046_4111.cpp:54: error: `x' undeclared (first use this function)
0_0_10822046_4111.cpp:54: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_10822046_4111.cpp:54: error: `y' undeclared (first use this function)