View Compilation Error

426061_0_0_18429.cpp: In function `bool TestOnce()':
426061_0_0_18429.cpp:8: error: `a' undeclared (first use this function)
426061_0_0_18429.cpp:8: error: (Each undeclared identifier is reported only once for each function it appears in.)
426061_0_0_18429.cpp:8: error: `b' undeclared (first use this function)