41a42,43
> #include <iostream>
>
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< virtual void print(ostream& out) const = 0;
---
> virtual void print(std::ostream& out) const = 0;
73c75
< ostream& operator<<(ostream& out, const Consumer& obj);
---
> std::ostream& operator<<(std::ostream& out, const Consumer& obj);
79c81
< ostream& operator<<(ostream& out, const Consumer& obj)
---
> std::ostream& operator<<(std::ostream& out, const Consumer& obj)
82c84
< out << flush;
---
> out << std::flush;