Why does toString() exist? It seems useless.

[bearophile]

Don:
> But the way it is formatted should be a property of the output stream, I 
> think, not a property of the object. Certainly this is the way C and C++ 
> I/O works.

You may be right, I am learning still a lot about such matters.

But how can the output stream know about the many ways to print a graph? (I don't know enough about C++ streams).

Bye,
bearophile