Which pointers do you have to delete to prevent leaks?

[Tiger58]

I had a program that had regular pointers and dynamic array pointers such as

int *numptr=#

and

int *arrayNum;

arrayNum=new int[5];

Now I obviously included the delete command delete [] arrayNum; for the second one (dynamic array) at the end of the program, but my teacher said I had forgotten to delete the other one (numptr). Do normal pointers have to be deleted at the end of the program as well??

[LB]

You only delete what you new
You only delete[] what you new[]

If you did not use new or new[], then you should not use delete or delete[].

Your teacher may have meant for you to null the pointer out when you were done with it to avoid a dangling pointer, which is different from a memory leak.

[Tiger58]

So I equal the pointer to zero?

[LB]

If you can use C++11, you would write pointer = nullptr;
If you can't use C++11 (e.g. the above doesn't work) then yes, you would usually write pointer = 0;

You should always null out pointers when you are done with them, even in both cases.

[N8hM4iN6]

i think it's not right to delete numptr;, cause it's not used with a new, so numptr is not pointing at a dynamic variable or array.

And when i test such code in my compiler, it's not working.

[LB]

There is a convoluted and rare reason to do such a thing:

int &num = *new int; //reference to heap-allocated int
int *numptr = # //these two lines are basically 'int *numptr = new int;'
delete numptr;
//or
delete #

It is a very rare and stupid case that you should never do or worry about - it is improper coding, but it is valid C++.