View Compilation Error

0_0_19214789_13098.cpp: In function 'int main()':
0_0_19214789_13098.cpp:9:5: error: 'cin' was not declared in this scope
     cin >> T;
     ^
0_0_19214789_13098.cpp:23:9: error: 'cout' was not declared in this scope
         cout << sum << endl;
         ^
0_0_19214789_13098.cpp:23:24: error: 'endl' was not declared in this scope
         cout << sum << endl;
                        ^