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



Task

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:

 20 degrees (b1) and 45 degrees (b2)
 -45 and 45
 -85 and 90
 -95 and 90
 -45 and 125
 -45 and 145
 29.4803 and -88.6381
 -78.3251 and -159.036


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



Test cases

 -70099.74233810938 and 29840.67437876723
 -165313.6666297357 and 33693.9894517456
 1174.8380510598456 and -154146.66490124757
 60175.77306795546 and 42213.07192354373


// Rosetta Code problem: http://rosettacode.org/wiki/Angle_difference_between_two_bearings
// by Jjuanhdez, 06/2022
 
print "Input in -180 to +180 range:"
getDifference(20.0, 45.0)
getDifference(-45.0, 45.0)
getDifference(-85.0, 90.0)
getDifference(-95.0, 90.0)
getDifference(-45.0, 125.0)
getDifference(-45.0, 145.0)
getDifference(-45.0, 125.0)
getDifference(-45.0, 145.0)
getDifference(29.4803, -88.6381)
getDifference(-78.3251, -159.036)
print "\nInput in wider range:"
getDifference(-70099.74233810938, 29840.67437876723)
getDifference(-165313.6666297357, 33693.9894517456)
getDifference(1174.8380510598456, -154146.66490124757)
end
 
sub getDifference(b1, b2)
    r = mod((b2 - b1), 360.0)
    if r >= 180.0  r = r - 360.0
    print r
end sub