View Compilation Error

0_0_10968494_23439.c: In function `f':
0_0_10968494_23439.c:7: error: `a' undeclared (first use in this function)
0_0_10968494_23439.c:7: error: (Each undeclared identifier is reported only once
0_0_10968494_23439.c:7: error: for each function it appears in.)
0_0_10968494_23439.c:7: error: `b' undeclared (first use in this function)