View Compilation Error

330392_0_13801.cpp: In function `int main()':
330392_0_13801.cpp:4: error: `a' undeclared (first use this function)
330392_0_13801.cpp:4: error: (Each undeclared identifier is reported only once for each function it appears in.)
330392_0_13801.cpp:4: error: `b' undeclared (first use this function)