pointer increment

[dkonerding at eagle.wesleyan.edu]

        Hi folks.  I'm a confused beginner C programmer who'd like to
understand pointer variables a bit better.  I have a small program.  I've done
the following:  int *ptr;

        Now, say I make ptr=1000 or hex 3e8.  I want to add one to the ptr, to
make it point to 1001, or hex 3e9.  Every time I do a ptr=ptr+1, it becomes
3ec.  How can I simply increment ptr by one?