I didn't know that the destructor could be called explicitly...

Question

I didn't know that the destructor could be called explicitly. Now I know that, but I have another problem: why is it called secondary when the program is done? Why is the object destroyed again? What is destroyed at the second time? Is the memory location cleared twice?
https://code.sololearn.com/cjSU1k9uJ9Ie/?ref=app

Answer 1

~ swim ~ , thanks