>> pretty much I understand how to get the values into the array inputted, I am just not sure how to validate that they are not negative, and how to get the array input to stop when the user inputs -1
Just do all of the validation within the loop. If scanf doesn't return 1 or the value scanned is less than -1 don't increment 'n'. Otherwise, if the value equals -1 break out of the loop. Otherwise, increment 'n'.
