# ------------------------------------------------------------
# A small program demonstrating how to remove every Nth element
# from an Array using clear, expressive Ruby patterns.
# ------------------------------------------------------------
#
# remove_every_nth returns a new array with every Nth element removed.
#
# Ruby arrays use zero‑based indexing, so we check (index + 1) % n != 0
# to keep elements that are *not* in the Nth position.
#
# The variable "size" captures the array length before the loop,
# which avoids repeatedly calling items.size inside the loop.
#
def remove_every_nth(items, n)
raise ArgumentError, "n must be a positive integer" if n <= 0
size = items.size # capture size once
result = Array.new # output array
# Perform a single pass over the array
for i in 0...size
result << items[i] if (i + 1) % n != 0
end
result
end
#
# Keeping the main execution block small and focused makes the program
# easy to extend. Here we demonstrate the function with a simple example.
#
data = (1..20).to_a # Example array: numbers 1–20
n = 3 # Remove every 3rd element
cleaned = remove_every_nth(data, n)
puts "Original: #{data.join(' ')}"
puts "After removing every #{n}-th element: #{cleaned.join(' ')}"
=begin
run:
Original: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
After removing every 3-th element: 1 2 4 5 7 8 10 11 13 14 16 17 19 20
=end
