View Compilation Error

746741_0_0_19735.cpp: In function `void enqueue(int)':
746741_0_0_19735.cpp:16: error: `SIZE' undeclared (first use this function)
746741_0_0_19735.cpp:16: error: (Each undeclared identifier is reported only once for each function it appears in.)
746741_0_0_19735.cpp: In function `int dequeue()':
746741_0_0_19735.cpp:27: error: `SIZE' undeclared (first use this function)
746741_0_0_19735.cpp: In function `bool bfs(int)':
746741_0_0_19735.cpp:34: error: `flag' undeclared (first use this function)