Created
November 26, 2009 12:27
-
-
Save RLGGHC/243426 to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
class Polynomial | |
def initialize(arg) | |
raise ArgumentError.new('We expect an array at least') unless arg.is_a? Array | |
raise ArgumentError.new('Need at least 2 coefficients') if arg.length < 2 | |
@exponents = [] | |
arg.reverse.inject(0) do |index,item| | |
@exponents.push( { "factor" => item, "exponent" => index }) unless item == 0 | |
index + 1 | |
end | |
end | |
def to_s | |
return "0=0" if @exponents.length == 0 | |
@exponents.reverse.inject("") do |result, exp| | |
f = exp["factor"] | |
e = exp["exponent"] | |
# show only the '+' when positive and not the first item, | |
# when negative, the '-' should always be shown | |
result << "+" if f > 0 && !result.empty? | |
result << "-" if f < 0 | |
# show the factor only when the absolute value is greater than 1 | |
result << f.abs.to_s if f.abs > 1 | |
# only show the x when the exponent is different from '0' | |
result << "x" unless e == 0 | |
# only show the exponent when it is not in the range (0..1) | |
result << "^#{e}" unless (0..1).include?(e) | |
result | |
end | |
end | |
end |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment