View Compilation Error

0_0_32065367_27643.cpp: In function 'int main()':
0_0_32065367_27643.cpp:6:8: error: 'cin' was not declared in this scope
  while(cin>>num&&num!=0)
        ^
0_0_32065367_27643.cpp:27:3: error: 'cout' was not declared in this scope
   cout<<n[0];
   ^
0_0_32065367_27643.cpp:30:9: error: 'endl' was not declared in this scope
   cout<<endl;
         ^