View Compilation Error

0_0_8677421_6430.cpp: In function `int bfs()':
0_0_8677421_6430.cpp:31: error: `ed' undeclared (first use this function)
0_0_8677421_6430.cpp:31: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_8677421_6430.cpp:34: error: `b' undeclared (first use this function)