View Compilation Error

0_0_18021673_739.cpp: In function 'int main()':
0_0_18021673_739.cpp:72:7: error: 'i' was not declared in this scope
   for(i=N;i>0;i--)
       ^
0_0_18021673_739.cpp:78:7: error: 'i' was not declared in this scope
   for(i=0;i<N;i++)
       ^