Question

New to StackOverflow here. I’m working on the first Euler problem and have run into an issue where I can get the statement to iterate through the array. It seems like it has something to do with the way I have the while loop setup but I can’t figure it out.

Here’s my code:

#euler problem 1

numbers = [3,5]
sum = 0
i=1
total=0

numbers.each do |number|
  while i * number < 10
    adder = i * number
    total += adder
    i += 1
    puts total
  end
end

puts total

The output is 3
9
18
18

Any idea why it isn’t processing the 5 in the array numbers?

Answer 1

Your problem is that i is declared outside the block so when number is five, i is already four and the while loop’s condition fails immediately because 20 < 10 is false. Try it like this:

numbers = [3,5]
sum = 0
total=0

numbers.each do |number|
  i = 1
  while i * number < 10
    #...
  end
end

puts total

If you put a little puts in your code you’ll see what’s going on:

i = 1
numbers.each do |number|
  puts "#{number}\ti = #{i}"
  while i * number < 10
    puts "\ti = #{i}"
    adder = i * number
    total += adder
    i += 1
  end
end

That will give you this output:

3   i = 1
    i = 1
    i = 2
    i = 3
5   i = 4

and you’ll see the problem with i.