If you deference ptr_thing: *ptr_thing, it points to '20'.
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cout << ptr_thing; //displays the address of the variable 'thing'
cout << *ptr_thing; //displays the contents at the address of the variable 'thing', 20 in this case.
Edit: If this is just something your doing in your spare time, system("pause") is OK, but don't make it a habbit unless you have a reason to. If you're using it to keep the console open, consider alternatives, like a couple calls to getchar();.