/in/foo.cc:1:1: error: 'include' does not name a type
 include <iostream>
 ^~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:9:2: error: 'cin' was not declared in this scope
  cin>>n;
  ^~~
/in/foo.cc:20:18: error: 'printf' was not declared in this scope
  printf("%-2.f",r);
                  ^