[Dev-C++] copy constructor

[John K. <jki...@po...>]

I'm in a c++ class, learning about overloading assignment operators. 
Why is it necessary to return a const reference? I understand the 
need to return a reference (sort of) -  it has to do with allowing 
chained calls to the assignmnet operator. But why return a const 
refernce?

Thanks,
John