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We do the math so you don't have to! |
Here is a simple way to test for a legal triangle in Ruby, for the Ruby Koans problems:
# 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)
# WRITE THIS CODE
if ( a <= 0 || b <= 0 || c <= 0 )
raise TriangleError, "non-positive side"
end
# also test for 3 sides cant make a triangle
s = (a + b + c) / 2.0
ok = (s - a) * (s - b) * (s - c) # this must be positive for a triangle
if (ok <= 0)
raise TriangleError, "bad a,b,c=#{a},#{b},#{c} s=#{s} ok=#{ok}"
end
if ( a == b )
if ( a == c )
return :equilateral
end
return :isosceles
else
if ( a == c || b == c )
return :isosceles
end
end
return :scalene
end
# Error class used in part 2. No need to change this code.
class TriangleError < StandardError
end
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