View Compilation Error

0_0_35970732_20168.cpp: In function 'int main()':
0_0_35970732_20168.cpp:6:8: error: 'cin' was not declared in this scope
  while(cin>>n)
        ^
0_0_35970732_20168.cpp:17:2: error: 'cout' was not declared in this scope
  cout<<b<<endl;
  ^
0_0_35970732_20168.cpp:17:11: error: 'endl' was not declared in this scope
  cout<<b<<endl;
           ^