local fmt = require "fmt"

---'cpx' returns integer index from 1 to 32 corresponding to compass point.
-- Input heading h is in degrees.
local function cpx(h)
    local x = math.floor(h /11.25 + 0.5) % 32
    if x < 0 then x += 32 end
    return x + 1
end

-- Printable compass points.
local compass_point = {
    "North",
    "North by east",
    "North-northeast",
    "Northeast by north",
    "Northeast",
    "Northeast by east",
    "East-northeast",
    "East by north",
    "East",
    "East by south",
    "East-southeast",
    "Southeast by east",
    "Southeast",
    "Southeast by south",
    "South-southeast",
    "South by east",
    "South",
    "South by west",
    "South-southwest",
    "Southwest by south",
    "Southwest",
    "Southwest by west",
    "West-southwest",
    "West by south",
    "West",
    "West by north",
    "West-northwest",
    "Northwest by west",
    "Northwest",
    "Northwest by north",
    "North-northwest",
    "North by west"
}

-- Function required by task.
local function degrees_to_compass_point(h) return compass_point[cpx(h)] end
local r = {
    0.0, 16.87, 16.88, 33.75, 50.62, 50.63, 67.5,
    84.37, 84.38, 101.25, 118.12, 118.13, 135.0, 151.87, 151.88, 168.75,
    185.62, 185.63, 202.5, 219.37, 219.38, 236.25, 253.12, 253.13, 270.0,
    286.87, 286.88, 303.75, 320.62, 320.63, 337.5, 354.37, 354.38
}

print("Index  Compass point         Degree")
local i = 0
for r as h do
    local index = i % 32 + 1
    local d = degrees_to_compass_point(h)
    fmt.print("%4d   %-19s %7.2f°", index, d, h)
    i += 1
end