Today at the Flatiron School we were introduced to a simple code challenge to prep us for the eventual future technical interview. I would imagine that the challenge is timed and needs to be completed within a specific timeframe. Let's put ourselves in the shoes of a recently graduated Flatiron student whose job is now to look for a job! - Ralph is an employer at a small tech company. He is here to give you the code challenge and watch you complete it. - Ralph "Write a script that sums all the multiples of 3 or 5 between 0 and any given number"

Think...Think...

Here is how we start:

1st step

 class Multiples
    attr_accessor :limit, :multiples
    def initialize(limit)
        @limit = limit
        @multiples = []
    end
 end

The instance variable multiples is an array that will eventually contain all the multiples of 3 or 5 between 0 and the limit @limit.

2nd step

def collect_multiples
    counter = 1
    while counter < @limit
        if counter % 3 == 0 || counter % 5 == 0
                @multiples << counter
        end
        counter +=1
    end
    @multiples
end

Here we are using the comparator operator || (or) to check the value of the local variable counter and push the result into the array @multiples Remember that the method returns the last expression evaluated, so @multiples needs to be placed before the closure of the method collect_multiples

3rd step

    def sum_multiples
        collect_multiples.inject {|sum, x| sum + x}
    end

For the final step, let's prompt the user for the limit:

class Multiples
    attr_accessor :limit, :multiples
    def initialize(limit)
        @limit = gets.chomp.to_i # prompt user and convert input into an Fixnum
        @multiples = []
    end
    def collect_multiples
        counter = 1
        while counter < @limit
            if counter % 3 == 0 || counter % 5 == 0
                @multiples << counter
            end
            counter +=1
        end
        @multiples
    end
    def sum_multiples
        collect_multiples.inject { |sum, x| sum + x}
    end
end
n = Multiples.new(@limit) # create new instance of the class Multiples
puts "#{n.sum_multiples}" # print the sum of the multiples

Try it out! In your bash run ruby name_of_file.rb and voila! If you give a limit of 1000 for example, you should get.... 233168. Bravo! you got it ;)

There is a great website for code challenges. Visit coderbyte choose your language of preference and get started!