Mã chấm: 268732

Main.cc: In function ‘int main()’:
Main.cc:9:5: error: ‘cin’ was not declared in this scope
     cin >> n;
     ^~~
Main.cc:9:5: note: suggested alternative: ‘sin’
     cin >> n;
     ^~~
     sin
Main.cc:18:5: error: ‘cout’ was not declared in this scope
     cout << pi << endl;
     ^~~~
Main.cc:18:5: note: suggested alternative: ‘cosl’
     cout << pi << endl;
     ^~~~
     cosl
Main.cc:18:19: error: ‘endl’ was not declared in this scope
     cout << pi << endl;
                   ^~~~
Main.cc:18:19: note: suggested alternative: ‘ynl’
     cout << pi << endl;
                   ^~~~
                   ynl