View Compilation Error

0_0_27853949_28401.cpp: In function 'int main()':
0_0_27853949_28401.cpp:10:8: error: 'cin' was not declared in this scope
  while(cin>>n)
        ^
0_0_27853949_28401.cpp:38:3: error: 'cout' was not declared in this scope
   cout<<fixed<<setprecision(2)<<summ<<endl;
   ^
0_0_27853949_28401.cpp:38:39: error: 'endl' was not declared in this scope
   cout<<fixed<<setprecision(2)<<summ<<endl;
                                       ^