View Compilation Error

0_0_6994017_22386.cpp: In function `int main()':
0_0_6994017_22386.cpp:6: error: `a1' undeclared (first use this function)
0_0_6994017_22386.cpp:6: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_6994017_22386.cpp:6: error: `b1' undeclared (first use this function)
0_0_6994017_22386.cpp:6: error: `a2' undeclared (first use this function)
0_0_6994017_22386.cpp:6: error: `b2' undeclared (first use this function)
0_0_6994017_22386.cpp:7: error: expected unqualified-id before '&' token