View Compilation Error

132959_0_26489.cpp: In function `int main()':
132959_0_26489.cpp:15: error: `a' undeclared (first use this function)
132959_0_26489.cpp:15: error: (Each undeclared identifier is reported only once for each function it appears in.)
132959_0_26489.cpp:15: error: `b' undeclared (first use this function)