loop.rb

require "benchmark"

include Benchmark

n = 100_000_000

def while_loop(n = 100_000_000)
  i = 0
  s = 0
  while i <= n
    s += i
    i += 1
  end
  s
end

def for_loop(n = 100_000_000)
  s = 0
  for i in 1..n
    s += i
  end
  s
end

def loop_loop(n = 100_000_000)
  i = 0
  s = 0
  loop do
    s += i
    i += 1
    break if i > n
  end
  s
end

def times_loop(n = 100_000_000)
  s = 0
  (n + 1).times do |i|
    s += i
  end
  s
end

def upto_loop(n = 100_000_000)
  s = 0
  1.upto(n) do |i|
    s += i
  end
  s
end

Benchmark.benchmark(CAPTION, 7, FORMAT) do |x|
  x.report("while:") { while_loop }
  x.report("for:") { for_loop }
  x.report("loop:") { loop_loop }
  x.report("times:") { times_loop }
  x.report("upto:") { upto_loop }
end

# Using Ruby 3.0.0
#               user     system      total        real
# while:    3.249034   0.000211   3.249245 (  3.250387)
# for:      6.781550   0.000000   6.781550 (  6.783788)
# loop:     8.140319   0.000000   8.140319 (  8.143120)
# times:    6.109319   0.003978   6.113297 (  6.144387)
# upto:     6.548618   0.000008   6.548626 (  6.579711)