View Compilation Error

0_0_39167807_11948.cpp: In function 'int eular(int)':
0_0_39167807_11948.cpp:11:35: error: 'cout' was not declared in this scope
   11 |                         ret*=n-1, cout << n << endl;
      |                                   ^~~~
0_0_39167807_11948.cpp:11:48: error: 'endl' was not declared in this scope
   11 |                         ret*=n-1, cout << n << endl;
      |                                                ^~~~