minGap

Write a static method minGap that takes an integer array
   as a parameter and that returns the minimum gap between adjacent values in
   the array.  The gap between two adjacent values in a list is defined as the
   second value minus the first value.  For example, suppose a variable called
   "list" is an array of integers that stores the following sequence of values.

        (1, 3, 6, 7, 12)


   The first gap is 2 (3 - 1), the second gap is 3 (6 - 3), the third gap is 1
   (7 - 6) and the fourth gap is 5 (12 - 7).  Thus, the call:

	minGap(list)

   Should return 1 because that is the smallest gap in the list.  Notice that
   the minimum gap could be a negative number.  For example, if list stores the
   following sequence of values:

        (3, 5, 11, 4, 8)

   The gaps would be computed as 2 (5 - 3), 6 (11 - 5), -7 (4 - 11), and 4 (8 -
   4).  Of these values, -7 is the smallest, so it would be returned.

   This gap information can be helpful for determining other properties of the
   list.  For example, if the minimum gap is greater than or equal to 0, then
   you know the list is in sorted (nondecreasing) order.  If the gap is greater
   than 0, then you know the list is both sorted and unique (strictly
   increasing).

   If you are passed a list with fewer than 2 elements, you should return 0.

   Write your solution to minGap below.