From: Dwight Shackelford <zydeholic@...>
Date: 2009-07-19T01:08:23+09:00
Subject: undefined method `*' for nil:NilClass (NoMethodError)

First off, I'm a student taking Ruby for the first time, so bear with
me.  I've tried doing a web search and a search of this forum, and
didn't see anything that addressed this specifically.

on line 18 of the following code (@height = @height * 1.1 in the method
oneYearPasses), I get the error message that is in the subject line.

If I take that same line of code and put it up in the area where I'm
defining variables, there is no error.  I'm suspecting something has
gone amiss in my method definition and the interpreter is getting
confused.

If I comment out that line, I get similar messages for my '>' operators
below that.

Probably a bump from you folks on that first problem will give me enough
info to solve the others as they come up.  Any help appreciated.
Thanks.

class OrangeTree
     @numFruit =0
     MAXAGE = 10
     FIRSTFRUIT = 20
     FIRSTHEIGHT = 3.0
     @age = 0
     @dead = false

     @height = FIRSTHEIGHT

    def getHeight
      return @height
    end

    def oneYearPasses
      if !@dead

        @height = @height * 1.1    #<<<<<<<<<<<< line causing error
        @age++

        if @age >= 3
          @numFruit = (1.2**(age -3)) * FIRSTFRUIT
        end

        if !(@age < MAXAGE)
          @dead = true
        end
      end
    end

    def countTheOranges
        return @numFruit
    end

    def pickAnOrange
        if @numFruit > 0
          @numFruit--
          puts {'That was delicious'}
        else
          puts {'There are no more oranges'}
        end
    end
end

myTree = OrangeTree.new
myTree.oneYearPasses
myTree.oneYearPasses
myTree.pickAnOrange
myTree.getHeight
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