View Compilation Error

0_0_20785888_5654.cpp: In function 'int main()':
0_0_20785888_5654.cpp:4:11: error: 'cin' was not declared in this scope
     while(cin >> n && n)  
           ^
0_0_20785888_5654.cpp:15:9: error: 'cout' was not declared in this scope
         cout << cnt << endl;  
         ^
0_0_20785888_5654.cpp:15:24: error: 'endl' was not declared in this scope
         cout << cnt << endl;  
                        ^
0_0_20785888_5654.cpp:18:13: error: expected '}' at end of input
     return 0;  
             ^