Your task is to complete a method that swaps the first and second half of an array of integers. For example, if the array contains the values

1 4 9 16 25 36
then after calling the method, it should contain the values 
16 25 36 1 4 9

If the array contains an odd number of elements, leave the middle element in place. For example,

1 4 9 16 25 36 45
becomes 
25 36 45 16 1 4 9