View Compilation Error

1_798_885_5226.cpp: In function 'int main()':
1_798_885_5226.cpp:8:10: error: 'std::ios' has not been declared
     std::ios::sync_with_stdio(false);
          ^
1_798_885_5226.cpp:9:11: error: 'cin' was not declared in this scope
     while(cin>>n){
           ^
1_798_885_5226.cpp:28:17: error: 'cout' was not declared in this scope
                 cout<<i<<endl;
                 ^
1_798_885_5226.cpp:28:26: error: 'endl' was not declared in this scope
                 cout<<i<<endl;
                          ^