Does "delete" in C++ undo the work of "new" funtion?

Question

Delete is used to release a pointer from a heap and not from stack. New creates a new memory allocation in a C++ program. eg new int;
delete *prt;

Answer 1

Memory allocations in C++ is a beast in itself. But simply put:

In terms of raw memory, new typically allocates memory using the C routine malloc which requests memory from the operating system.

There's quite a few differences between operating systems as to how hardware memory is managed however at a high level you get a reserved chunk of memory the size of your data type.

Delete typically calls the C routine free which returns that allocated block of memory to the operating system.

In terms of malloc and free, yes delete undoes what new did.

However, in C++ we have objects that have constructors and destructors and there's no guarantee that the destructor undoes all of the work that was done when the constructor was called.

I guess we could say the answer is yes and no, depending on where you draw the line.