Easy question? Need help understanding overloading assignment operator

[bool maybe]

It seems to me that the standard definition for an overloaded assignment operator is something along these lines:

Vehicle& operator =(const Vehicle& rhs);

I don't really understand why it's typical to start off overloading the assignment operator by specifying the return type of the function as class&. void would make a lot more sense to me. is the reason for doing this so that, for example:

SomeClass a, b, sum;
cout << "this is the sum: " << sum = a+b;

would be able to display the value of sum? Hopefully this question makes sense.

[helios]

Yes.
Also:

a=b=c;