Delete pointer

Hi,
I've just read this topic - "Lesson 6: An introduction to pointers"

Quote:

---

The delete operator frees up the memory allocated through new. To do so, the syntax is as in the example.

delete ptr;

---

Could you tell me more about that and give me any example?
How can I use it?

Code:

---

int x = 10;
int *ptr;
ptr = &x;
cout << ptr << " " << *ptr << endl;

delete ptr;    //Is it ok?

cout << ptr << " " << *ptr << endl; //What should be as a result? I've got error: memory violation.

---

int* x = new int;
cout << ptr << " " << *ptr << endl;
delete x;

You can only delete what you new.
You cannot use *ptr after you've deleted it.

Quote:

---

Originally Posted by Chris_thf

Hi,

Code:

---

int x = 10;
int *ptr;
ptr = &x;
cout << ptr << " " << *ptr << endl;

delete ptr;    //Is it ok?

cout << ptr << " " << *ptr << endl; //What should be as a result? I've got error: memory violation.

---

---

You cannot delete pointer to x, because you didn't allocate memory of x on your own.

OK, I understand.
Thank you very much. :)