const thirdAngle = (angle1, angle2) => (angle1 && angle2 && (angle3 = 180 - (angle1 + angle2)) > 0) ? angle3 : 'Invalid - Sum of all angles of a triangle should be 180 degrees';

import List exposing (all, sum)
import Maybe exposing (andThen, map)


isAngle : Int -> Bool
isAngle angle =
    angle > 0 && angle < 180


maybeAngles : List Int -> Maybe (List Int)
maybeAngles angles =
    if all isAngle angles && sum angles < 180 then
        Just angles

    else
        Nothing


third : Int -> Int -> Maybe Int
third first second =
    maybeAngles [ first, second ]
        |> map (sum >> (-) 180)

defmodule Triangle do
  def third_angle(a, b) when is_integer(a + b) # will not qualify if either isn't an integer
                         and a + b < 180 
                         and a > 0
                         and b > 0 do
    180 - a - b
  end
end

func thirdAngle(a, b int) (int, error) {
    if (a + b) >= 180 {
        return 0, errors.New("Input angles sum is greater than or equal to 180 degress, this cannot be a triangle")
    }
    if a == 0 || b == 0 {
        return 0, errors.New("Input angle cannot be zero, cannot be a triangle")
    }
    angle := 360 - a - b // sum of angles must be 360 degress
    return angle, nil
}

thirdAngle←{r←180-+/⍵ ⋄ (r<0)∨0∊⍵: 'This is not a triangle!' ⋄ r}

      thirdAngle 30 60
90
      thirdAngle 60 60
60
      thirdAngle 43 78
59
      thirdAngle 10 20
150

function thirdAngle {
  echo $((180 - $1 - $2))
}

> thirdAngle 30 60
90

> thirdAngle 60 60
60

> thirdAngle 43 78
59

> thirdAngle 10 20
150

function thirdAngle(a,b) {
    return 180-a-b;
}