View Compilation Error

0_0_4327798_27762.cpp:18: error: expected init-declarator before "front"
0_0_4327798_27762.cpp:18: error: expected `,' or `;' before "front"
0_0_4327798_27762.cpp: In function `void bfs(int)':
0_0_4327798_27762.cpp:54: error: `front' undeclared (first use this function)
0_0_4327798_27762.cpp:54: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_4327798_27762.cpp:54: error: `tail' undeclared (first use this function)
0_0_4327798_27762.cpp:56: error: `que' undeclared (first use this function)