View Compilation Error

0_0_5241732_30774.cpp: In function `int main(int, char**)':
0_0_5241732_30774.cpp:29: error: `a' undeclared (first use this function)
0_0_5241732_30774.cpp:29: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_5241732_30774.cpp:29: error: expected `;' before '}' token