>must be somehow automatically included based on my compiler setup.
That's nice. Now forget about it. Your code is not portable if you rely on such things.

>doesn't that take care of any memory leaks?
Yes, but only because you correctly assigned the memory to tester by using a pointer to a pointer. If you had not made that change, no amount of deleting would stop the memory leak. Once again, I urge you to read the tutorial so that you know what the problem was and why the fix fixed it.