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


Angles:= [[20, 45]
        ,[-45, 45]
        ,[-85, 90]
        ,[-95, 90]
        ,[-45, 125]
        ,[-45, 145]
        ,[29.4803, -88.6381]
        ,[-78.3251, -159.036]
        ,[-70099.74233810938, 29840.67437876723]
        ,[-165313.6666297357, 33693.9894517456]
        ,[1174.8380510598456, -154146.66490124757]
        ,[60175.77306795546, 42213.07192354373]]
 
for i, set in angles
    result .= set.2 " to " set.1 " = " Angle_difference_between_two_bearings(set) "`n"
MsgBox, 262144, , % result
return
 
Angle_difference_between_two_bearings(set){
    return (diff := Mod(set.2, 360) - Mod(set.1, 360)) >180 ? diff-360 : diff
}