control_flow_within_blocks.md

🔒 Short-Circuit Iterators with break, next, and return

Blocks can control the flow of their enclosing method differently depending on context. Use break to exit an iterator, next to skip, or return to exit the entire method. Understand these semantics to avoid surprises.

def find_first_even(array)
  array.each do |n|
    return n if n.even?
  end
  nil
end

puts find_first_even([1,3,4,5])
# => 4

[1,2,3].each do |n|
  next unless n.even?
  puts "Found even: #{n}"
  break
end
# => Found even: 2