View Compilation Error

0_0_36710028_24242.cpp: In function 'int main()':
0_0_36710028_24242.cpp:15:2: error: 'cin' was not declared in this scope
  cin >> n;
  ^
0_0_36710028_24242.cpp:17:2: error: 'cout' was not declared in this scope
  cout << k << endl;
  ^
0_0_36710028_24242.cpp:17:15: error: 'endl' was not declared in this scope
  cout << k << endl;
               ^