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class Polynomial | |
attr_reader :coeffs | |
def initialize(coeffs) | |
raise ArgumentError, "Need at least 2 coefficients", caller if coeffs.length <= 2 | |
@coeffs = coeffs | |
end | |
def to_s | |
polynom = "" #initialize empty string to create polynomial expression | |
@coeffs.each_with_index do |coeff,index| | |
exponent = @coeffs.length - index - 1 #countdown exponent value starting from 1 less than number of coefficients passed | |
if coeff != 0 #Don't do anything if 0 value is passed for current coefficient | |
polynom += "+" if (coeff >= 0 and polynom != "") | |
#Add a plus sign if coefficient is positive unless on first item of array or there has been no output so far | |
polynom += coeff.to_s unless (coeff == 1 and exponent != 0) | |
#Add the coefficient to polynomial unless is a 1 value or on the final coefficient | |
polynom.chop! if coeff == -1 | |
#Remove the 1 if the coefficient is -1 (leaving just a minus sign) | |
polynom += "x" unless exponent == 0 | |
#Add x for all but last coefficient | |
polynom += "^" + exponent.to_s if exponent > 1 | |
#Add ^exponent for all but last 2 coefficients | |
end | |
end | |
polynom == "" ? "0" : polynom #set polynom to "0" if nothing has been output | |
end | |
end |
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