Problem Statement

Finding the angle between two bearings is often confusing.[1]

Find the angle which is the result of the subtraction b2 - b1, where b1 and b2 are the bearings. Input bearings are expressed in the range   -180   to   +180   degrees. The  result  is also expressed in the range   -180   to   +180   degrees.

Compute the angle for the following pairs:

Allow the input bearings to be any (finite) value.

Let's start with the solution:

precision 4

define s1 = 0, s2 = 0

dim b1[20, -45, -85, -95, -45, -45, 29.4803, -78.3251]
dim b2[45, 45, 90, 90, 125, 145, -88.6381, -159.036]

arraysize s1, b1
arraysize s2, b2

if s1 = s2 then

	for i = 0 to s1 - 1

		let r = (b2[i] - b1[i]) % 360

		if r >= 180 then

			let r = r - 360

		endif

		print "bearing 1: ", b1[i], " bearing 2: ", b2[i], " difference: ", r

	next i

endif