I assume you need to have something like this as a result? (All last and first col and row values need to become a WALL)
In order to achieve that, you need to think about what conditions need to be met in order for a WALL to be initialised into the Array.
During the for-loop, you need to check
whether the row value is at the first or last row OR col is at the first or last value. If one of these is
true, put a WALL instead of an EMPTY into the Array. If none of these are true, an EMPTY will be put into the array.
It might sound confusing what I just said, but translate what I just tried to broadly describe into C++ and it should be solved, it's hard to describe conditions when you yourself are going to sound like a confusing computer program..
Ask away if you need anymore tips for this
edit: I'm actually not sure which values your docent wants to see within the array. I went with 0 and 1 because it seemed easy, but WALL does not have a specified value in your code as far as I can see, so you might want ot add WALL = 1 or something