# private and protected

class Train
        def initialize(length,seats)
                @length = length
                @seats = seats
        end

# private means "only without object qualifier"
        # private
# protected means "only in same class or ones that inherit from it
        protected

        def getseats()
                return @length * @seats
        end

# Cancel out ongoing restrictions imposed by previous "private" or "protected"
# make the rest public (i.e. return to default permission, which is allow-all)

        public
        def getcapacity()
                # next line FAILS on private because of explicit object being used
                # but it WORKS if the method called is protected.
                return (self.getseats * 1.4).to_i
                # return (getseats * 1.4).to_i # means exactly the same ... works for private too!
        end

        def Train.totalpassengers(*choices)
                so_far = 0
                for choice in choices
                        addon = choice.getcapacity
                        so_far += addon
                end
                return so_far
        end
end

paddington = Train.new(5,78)
looe = Train.new(1,73)

p paddington.getcapacity
p looe.getcapacity

overall_capacity = Train.totalpassengers(paddington,looe)
puts overall_capacity

# Next line will fail at run time - call to protected method from outside class
p looe.getseats

__END__

munchkin:rpj12 grahamellis$ ruby current
546
102
648
current:47: protected method `getseats' called for #<Train:0x109730c08 @seats=73, @length=1> (NoMethodError)
munchkin:rpj12 grahamellis$