View Compilation Error

0_0_39253281_25991.cpp: In function 'std::ostream& operator<<(std::ostream&, poly)':
0_0_39253281_25991.cpp:11:9: error: 'i' was not declared in this scope
   11 |     FOR(i, 0, F.size() - 1) ou << F[i] << ' ';
      |         ^
0_0_39253281_25991.cpp:11:5: error: 'FOR' was not declared in this scope
   11 |     FOR(i, 0, F.size() - 1) ou << F[i] << ' ';
      |     ^~~