why function chaining is working without returning reference from overloaded operator

Question

Hi

Please refer below code:
https://code.sololearn.com/cv3zt0kMdApu

why c0+c2+c3 is working fine even though I am not returning reference from overloaded operator?

Answer 1

References to the object (*this) are typically returned from:
Prefix increment
Prefix decrement
Assignment
Compound assignment (+=, ...)

These operators usually work on and change the object itself, so you return a reference to be able to correctly chain calls to "mutating" operators. Most other operators, like +, -, ..., do not change their parameters and therefore need to create a new instance to store the result, which needs to be returned as a copy due to scope rules.
Other operators might return references as well, just usually not to the object, e.g. the subscript operator.
However, ultimately it depends upon what your operator does. Since you are free to overload them however you want, it might function in a completely different way. These are just suggestions because most people will expect your overloaded operator to work in a certain way, based on their experiences with how it behaves normally.

Answer 2

I'm guessing it should work the way it would with regular numbers

c4 = ( ( c0 + c1 ) + c2 )

I could be wrong though. Let's see what community says ...

Answer 3

Yes lpang is right.
first c0 and c1 is added and then the returned object gets added to c2.

Answer 4

Seems this is logically correct and working also.... Do we never need reference return from overloaded operator ? This is making me confuse

Answer 5

Yeah got it... Thank you so much Shadow

Answer 6

Does a reference have to be returned for the operator to work?

Answer 7

No it's not mandatory... For two object addition , it's fine... My query arised due to c0+C1+C2 as I thought it should be a case of function chaining..