View Compilation Error

0_0_4157969_18240.cpp: In function `int main()':
0_0_4157969_18240.cpp:11: error: `i' undeclared (first use this function)
0_0_4157969_18240.cpp:11: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_4157969_18240.cpp:15: error: `n' undeclared (first use this function)