Ruby solution for Project Euler problem 1

euler1.rb

# https://projecteuler.net/problem=1

puts "Find the sum of all the multiples of 3 or 5 below which number?"
STDOUT.flush #clears the buffer
max_num = Integer(gets.chomp)

def sum_x3_x5(num)
  sum = 0
  (1..num).each do |n|
    sum = sum + n if (n % 3 == 0) || (n % 5 == 0) #Add if n is divisible by 3 or 5
  end
  sum #return
end

puts "Sum = " + sum_x3_x5(max_num).to_s