View Compilation Error

0_0_28059792_31348.cpp: In function 'int main()':
0_0_28059792_31348.cpp:6:9: error: 'cin' was not declared in this scope
  while (cin >> a >> b)
         ^
0_0_28059792_31348.cpp:12:3: error: 'cout' was not declared in this scope
   cout << c << endl<<endl;
   ^
0_0_28059792_31348.cpp:12:16: error: 'endl' was not declared in this scope
   cout << c << endl<<endl;
                ^