require "math2"

local function subtract(b1, b2)
    local d = (b2 - b1) % 360
    if d < -180 then d += 360 end
    if d >= 180 then d -= 360 end
    return math.toplaces(d, 4)
end

local pairs = {
    { 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}
}

print("Differences (to 4dp) between these bearings:")
for pairs as pair do
    local [p1, p2] = pair
    local diff = subtract(p1, p2)
    local offset = p1 < 0 ? " " : "  "
    print($"{offset}{p1} and {p2} -> {diff}")
end