Thread: Delete pointer

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

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.