View Compilation Error

0_0_1998896_7475.cpp: In function `int main()':
0_0_1998896_7475.cpp:152: error: `i' undeclared (first use this function)
0_0_1998896_7475.cpp:152: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_1998896_7475.cpp:152: error: `vec' undeclared (first use this function)