Write a function named has_midpoint that accepts three integers as parameters and returns True if one of the integers is the midpoint between the other two integers; that is, if one integer is exactly halfway between them.
Your function should return False if no such midpoint relationship exists.
The integers could be passed in any order; the midpoint could be the 1st, 2nd, or 3rd. You must check all cases.
Calls such as the following should return True:
has_midpoint(4, 6, 8)
has_midpoint(2, 10, 6)
has_midpoint(8, 8, 8)
has_midpoint(25, 10, -5)
Calls such as the following should return False:
has_midpoint(3, 1, 3)
has_midpoint(1, 3, 1)
has_midpoint(21, 9, 58)
has_midpoint(2, 8, 16)
