Why 6 calls to destructor for 5 objects?

Question

I don’t understand why the output is 6, can someone please explain it?

https://code.sololearn.com/cShhwiOB4219/?ref=app

Answer 1

It's because the maximum capacity of the vector has been reached.
When you push_back a new value the vector has to reallocate a new, and bigger array to hold the new value. This involves copying the object and destructing the old.

The 1 extra is just for a temporary in the constructor of the vector.
It creates the object, copies it 4 times, then destructs it.