View Compilation Error

0_0_5169188_19303.cpp: In function `int main()':
0_0_5169188_19303.cpp:11: error: `i' undeclared (first use this function)
0_0_5169188_19303.cpp:11: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_5169188_19303.cpp:12: error: `a' undeclared (first use this function)