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
#
def triangle(a, b, c)
  if ((a || b || c) <= 0)
    raise TriangleError, "Triangle side has invalid length"
  end
  
  if ((a + b <= c) || (a + c <= b) || (b + c <= a))
    raise TriangleError, "Lengths of any two sides of a triangle must add up to more than the length of the third side"
  end
  
  if (a == b && a == c)
    return :equilateral
  elsif (a == b || a == c || b == c)
    return :isosceles
  else
    return :scalene
  end
end

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