ruby 运行报错 uninitialized constant Sequence (NameError)。
看着《The Ruby Programing》这本书的例子自己写了2个类。
Sequence.rb
##this class represents a sequence of numbers characterized by the three#parameters from, to, and by. The numbers x in the sequence obey the #following two constraints:# # from <= x <= to# x = from + n*by, where n is aninteger#class Sequence #This is an enumerable class; it defines an each iterator below. #initialize newly created instances of the class def initialize(from, to, by) #Just save our paramerters into instance variables for later use @from, @to, @by = from, to, by #Note parallel assignmendt and @ prefix end #this is the iterator required by the Enumerable module def each x = @from #Start at the starting point while x <= @to #while we haven't reached the end yield x #pass x to rhe block associated with the iterator x += @by #Increment x end end #Define the length method (following arrarys) to return hte numgber of #values in the sequence def length return 0 if @from > @to Integet((@to - @from)/@by) + 1 end #Define another name for the same method #It is common for methods to have multiple names in Ruby alias size length #size is now a synonym for length #Override the array-access operator give random accesss to give random access to the sequence def[](index) return nil if index < 0 #Return nul for negative indexes v = @from + index*@by #compute the value if v <= @to #if it is part of the sequence v #return it else #otherwise nil end end #Override arichmetic operators to return new Squence objects def *(factor) Squence.new(@from*factor, @to*facotor, @by*factor) end def +(offset) Squence.new(@from + offset, @to + offset, @by) endend
s = Sequence.new(1, 10, 2) #from 1 to 10 by 2'ss.each {|x| print x}print s[s.size - 1]t = (s+1)*2