マルチスケールシミュレーション特論10

!Mac OS X-10.15.7 !ruby-2.7.1p83

Recursive Fibonacci

講義ページリンク

チャート式ruby-V(Recursive Fibonacci)

内容

rubyで再帰処理

課題

フィボナッチ数列を計算するプログラムの作成

解答例

"assert_equal.rb"

#!/usr/bin/env ruby
# frozen_string_literal: true

def fib(n)
  if n.zero?
    0
  elsif n == 1
    1
  else
    fib(n - 1) + fib(n - 2)
  end
end

require './assert_equal'
[[0, 0], [1, 1], [2, 1], [3, 2], [4, 3],
 [5, 5], [6, 8], [7, 13], [8, 21]].each do |index, expected|
  puts assert_equal(expected, fib(index))
end

出力

> ruby fibonacci.rb
expected: 0
result: 0
succeeded in assert_equal.

expected: 1
result: 1
succeeded in assert_equal.

expected: 1
result: 1
succeeded in assert_equal.

expected: 2
result: 2
succeeded in assert_equal.

expected: 3
result: 3
succeeded in assert_equal.

expected: 5
result: 5
succeeded in assert_equal.

expected: 8
result: 8
succeeded in assert_equal.

expected: 13
result: 13
succeeded in assert_equal.

expected: 21
result: 21
succeeded in assert_equal.

NOTE

• 再帰処理は他のプログラミング言語と同じように書ける
• rubocopいわくfibというmethod名は短いらしいけど特に問題ないので無視する

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• source ~/multiscalesim_toku/grad_members_20f/members/lynd2299/mss10.org