Can I delete a memory previously allocated dynamically, but with a different pointer?

Question

I was making a program for linked list in C++. To implement the concept, I created a pointer 'start' globally, pointing to the first element of the list.

After completion of the program I tried to delete all memory allocated dynamically to prevent memory leaks, by accessing successive nodes using the start and another locally declared pointer 'p'. Here, I used a pointer pointing to the same correct addresses, but this pointer was not the one used for memory allocation, but was declared locally like any normal pointer.

My question is - Is it possible to delete the dynamically allocated memory by using the normal pointers pointing to the same location?

Answer 1

Yes you can. This is valid:

int* p = new int;
int* q = p;
delete q;

The equivalent when using new[] :

int* p = new int[123];
int* q = p;
delete[] q;

Substitute int* with your pointer type. Whether to set the pointers to nullptr afterwards is up for debate.

Answer 2

So long as the pointer has the same type and value ¹ as the one you got back from new , yes you can use that as the delete argument.

Also, remember to use delete[] if you used new[] .

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¹ Qualifiers ( const , volatile ) don't matter. Note that you can also use a pointer to a base class with a virtual destructor.