Why I had a segmentation fault using copy assignment C++

Question

Reading a book, I was trying to understand how copy assignment works. Here is the code:

https://code.sololearn.com/c6A131A12a1A

Basically is a very simple Vector that allocates dynamic memory, but I have a problem, I have a segmentation fault, using -fsanitize=address tells me that the error is at line 100.

Here is the error:
AddressSanitizer: attempting free on address which was not malloc()-ed:

Which I don't understand why that error, if I delete line 100, error is gone and my code works, I'm able to print the copied values, but I think that the old memory still there.

How can I solve this? I googled some examples and all of them uses delete[] var.

Answer 1

I'm guessing that was because you were trying to point <element> to another memory block address <new_elements> while in fact <element> had been released (deleted).

I guess maybe you can try to resize <element> instead, rather than allocating <new_elements>. After all, previous contents in <element> is going to be overwritten with elements from <v>.

Answer 2

Ipang thanks for answer me! I figure out the solution, the sanitizer is clear "attempting to free on address which was not malloc()"
In the line 145, the constructor that is called Vector v; doesn't allocate any memory so... Is trying to delete memory that is not allocated.
I had two options, find a way to allocate memory when Vector v; constructor is called or just do
Vector v(n).
Doing that now I had memory allocated and can be deleted.

Answer 3

Good job! Eduardo Perez Regin 👍