Question

I’m wondering if I have 2 pointers pointing same object, and then I delete it using pointer 1, will it still be in memory and pointer 2 will point null, or object will stay in memory and I need to use delete pointer 2 to free it?

I mean:

int *p1, *p2;
p1=new int;
p2=p1;
*p1=5;
p2=p1;
delete p1;

int x=*p2;
//Error or x=5?

Answer 1

• The object will be gone.
• Pointer 2 will not be a null pointer, but a dangling pointer, with its previous but now-invalid value; doing anything with it will be an error.¹
• That’s exactly true for pointer 1, too. There will be no difference between the two.

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^{1 – Well, UB, not an “error” per se. But don’t do it.}