Challenge 2: Splat Args — Solution

def average(*numbers)
  return 0 if numbers.empty?

  numbers.sum / numbers.length.to_f
end

puts average(4, 8, 15, 16, 23, 42)
puts average(10, 20)
puts average

=begin
Output:
18.0
15.0
0

Notes:
- *numbers collects every positional argument into a single Array, so
  average(4, 8, 15, 16, 23, 42) receives numbers as [4, 8, 15, 16, 23, 42].
- return 0 if numbers.empty? is the modifier-if early-exit pattern from
  Chapter 3, guarding against division by zero.
- numbers.length.to_f forces float division deliberately (Chapter 2's
  integer-division gotcha) — without .to_f, an average like 18/6 would
  truncate to an integer instead of showing decimal precision when it's
  present.
=end