View Compilation Error

0_0_11661539_21244.c:3:17: queue: No such file or directory
0_0_11661539_21244.c:4: error: syntax error before "namespace"
0_0_11661539_21244.c: In function `bfs':
0_0_11661539_21244.c:30: error: `queue' undeclared (first use in this function)
0_0_11661539_21244.c:30: error: (Each undeclared identifier is reported only once
0_0_11661539_21244.c:30: error: for each function it appears in.)
0_0_11661539_21244.c:30: error: `node' undeclared (first use in this function)
0_0_11661539_21244.c:30: error: `Q' undeclared (first use in this function)
0_0_11661539_21244.c:31: error: syntax error before "a"
0_0_11661539_21244.c:32: error: `a' undeclared (first use in this function)
0_0_11661539_21244.c:46: error: `next' undeclared (first use in this function)