View Compilation Error

0_0_18431116_20041.cpp: In function 'int main(int, const char**)':
0_0_18431116_20041.cpp:6:9: error: 'cin' was not declared in this scope
  while (cin >> n)
         ^
0_0_18431116_20041.cpp:11:3: error: 'cout' was not declared in this scope
   cout << sum << endl << endl;
   ^
0_0_18431116_20041.cpp:11:18: error: 'endl' was not declared in this scope
   cout << sum << endl << endl;
                  ^