ruby - Can't always access value of instance variable without @ even with attr_accessor -

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this question has answer here:

how come error nomethoderror: undefined method '+' nil:nilclass line puts test prints out 1 know value initialized?

class testclass   attr_accessor :test   def initialize()     @test = 1   end    def testfn     puts test     test = test + 1   end end  t = testclass.new t.testfn

it works if change test @test thought didn't have if had attr_accessor :test

when assigning value instance variable through accessor / writer, have use self, otherwise ruby interpreter thinks local variable. in case, testfn code should this:

def testfn   puts test   self.test = test + 1 end

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