Overloading the =Operator

[UofFprogrammer]

Hello,
I was taking a look at overloading the = operator in a C Plus Plus book. Part of the code of the overloaded =operator included checking for the case when the same object was on both sides of the equal sign. When and why would you have a situation like this?

someobject1=someobject1;

Thank You

[Cucumber]

Hello,
I was taking a look at overloading the = operator in a C Plus Plus book. Part of the code of the overloaded =operator included checking for the case when the same object was on both sides of the equal sign. When and why would you have a situation like this?

someobject1=someobject1;

Thank You

yes
thats why that safety code is included in the operator=

[UofFprogrammer]

I understand the safety code part, but I couldn't think of an intentional situation where the code would have same object on both sides of the assignment operator.

[weaknessforcats]

When and why would you have a situation like this?

Code: ( text )
someobject1=someobject1;

You can't prevent some nutcase from doing this so you have to code defensively.

This is important where objects with dynamically allocated assets are concerned. The left object has to delete its contents in preparation for a copy of the right object's contents. In this bizarre case the object would have deleted its own contents and then crashed the program trying to make a copy of them.

It's easy enough to avoid the whole mess by just disallowing self-assignment.

[UofFprogrammer]

You can't prevent some nutcase from doing this so you have to code defensively.

This is important where objects with dynamically allocated assets are concerned. The left object has to delete its contents in preparation for a copy of the right object's contents. In this bizarre case the object would have deleted its own contents and then crashed the program trying to make a copy of them.

It's easy enough to avoid the whole mess by just disallowing self-assignment.

Weaknessforcats, you hit the nail on the head. That was the situation that was in the book with dynamically allocated assets being deleted before being reassigned. I was curious if there was ever a situation where that code would be done intentionally or if it was just programmer error.

Thanks for the response!