How to detect if a pointer was deleted and securely delete it?

Question

In C++ How to decide or know if a pointer was deleted before??

when i tried to delete a pointer that was previously deleted in another part of the c

Answer 1

This is a good question, but one of the fundamental truths of working in a manually memory managed environment (like C/C++ and its cousins) is that there's no good way of looking at a pointer after the fact and asking whether it's valid-- once it's become invalid, it's gone, and looking at it is prone to blowing up. Your job is to make sure that it's never deleted or freed more than once, and never accessed after that time.

Definitely look at the smart pointers, which were invented to make programmer's lives easier in just these circumstances. (The more traditional method is to be careful, not screw it up, and then maybe assign NULL to the pointer when you know it's been deleted, as Alok says.)