C++ Memory Management is broken

Question

I'm messing around with memory management in c++, but I got weird output. It doesn't say its an error or warning, it says free(): double free detected in tcache2. What does it mean?
https://code.sololearn.com/coS0bmKqyRJ7/?ref=app

Answer 1

You are doing free and delete on ptr.

free(ptr);

delete ptr;

Please remove one of them.

Answer 2

Remove delete ptr; usually delete is used with new. And free with malloc and calloc.