triangle.rb

# Triangle Project Code.

# Triangle analyzes the lengths of the sides of a triangle
# (represented by a, b and c) and returns the type of triangle.
#
# It returns:
#   :equilateral  if all sides are equal
#   :isosceles    if exactly 2 sides are equal
#   :scalene      if no sides are equal
#
# The tests for this method can be found in
#   about_triangle_project.rb
# and
#   about_triangle_project_2.rb
#
# TODO: There must be a better way to do this
def triangle(a, b, c)
  if (a < 1 || b < 1 || c < 1) ||
    (a + b <= c || a + c <= b || b + c <= a)
    raise TriangleError, "Invalid triangle sides"
  end

  if a == b && a == c && b == c
    return :equilateral
  end

  if a == b || a == c || b == c
    return :isosceles
  end

  :scalene
end

# Error class used in part 2.  No need to change this code.
class TriangleError < StandardError
end