Why in some cases we need to return reference from assignment operator overloading function?

Question

1st Case :-
Void operator=(const Test& obj)
{
If(this != &Obj)
{
x=new int;
*x=*obj.x;
}
}

2nd Case :-
Test& operator=(const Test& obj)
{
If(this != &Obj)
{
x=new int;
*x=*obj.x;
}
return *this;
}

Above both the codes for assignment operator overloading works fine. Then why in Second case why we need to have return type "Test&" when normal void as return also works.

Answer 1

We return a reference because then it allows us to chain multiple functions/operators.

For example something like this:
Test a, b, c;
c = b = a;

Or a.function1().function2();
( If function1 returns a reference )