View Compilation Error

967050_0_0_11681.cpp: In function `int main()':
967050_0_0_11681.cpp:5: error: `a' undeclared (first use this function)
967050_0_0_11681.cpp:5: error: (Each undeclared identifier is reported only once for each function it appears in.)
967050_0_0_11681.cpp:5: error: `b' undeclared (first use this function)