View Compilation Error

0_0_39478542_1550.cpp: In function 'int calctail(int, int)':
0_0_39478542_1550.cpp:7:33: error: 'cout' was not declared in this scope
    7 |                                 cout <<'0'<< i << ' ';
      |                                 ^~~~
0_0_39478542_1550.cpp:10:33: error: 'cout' was not declared in this scope
   10 |                                 cout << i << ' ';
      |                                 ^~~~
0_0_39478542_1550.cpp: In function 'int main()':
0_0_39478542_1550.cpp:20:16: error: 'cin' was not declared in this scope
   20 |         while (cin >> a >> b) {
      |                ^~~