练习31: 做出决定–笨方法学ruby在线-昊天SEO

这本书的上半部分，你打印出了一些东西，并且调用了函式，不过一切都是直线式进行的。你的脚本从最上面一行开始，一路运行到结束，但其中并没有决定程序流向的分支点。现在你已经学会了 if、else和 elsif，你就可以开始建立包含条件判断的脚本了。
上一个脚本中你写了一系列的简单提问测试。这节的脚本中，你将需要向使用者提问，依据使用者的答案来做出决定。把脚本写下来，多多捣鼓一阵子，看看他的运作原理是什么。

def prompt
  print <span class="s2">"> "</span>
end

puts <span class="s2">"You enter a dark room with two doors.  Do you go through door #1 or door #2?"</span>

prompt<span class="p">;</span> <span class="nv">door</span> <span class="o">=</span> gets.chomp

<span class="k">if</span> <span class="nv">door</span> <span class="o">==</span> <span class="s2">"1"</span>
  puts <span class="s2">"There's a giant bear here eating a cheese cake.  What do you do?"</span>
  puts <span class="s2">"1. Take the cake."</span>
  puts <span class="s2">"2. Scream at the bear."</span>

  prompt<span class="p">;</span> <span class="nv">bear</span> <span class="o">=</span> gets.chomp

  <span class="k">if</span> <span class="nv">bear</span> <span class="o">==</span> <span class="s2">"1"</span>
    puts <span class="s2">"The bear eats your face off.  Good job!"</span>
  elsif <span class="nv">bear</span> <span class="o">==</span> <span class="s2">"2"</span>
    puts <span class="s2">"The bear eats your legs off.  Good job!"</span>
  <span class="k">else</span>
    puts <span class="s2">"Well, doing #{bear} is probably better.  Bear runs away."</span>
  end

elsif <span class="nv">door</span> <span class="o">==</span> <span class="s2">"2"</span>
  puts <span class="s2">"You stare into the endless abyss at Cthuhlu's retina."</span>
  puts <span class="s2">"1. Blueberries."</span>
  puts <span class="s2">"2. Yellow jacket clothespins."</span>
  puts <span class="s2">"3. Understanding revolvers yelling melodies."</span>

  prompt<span class="p">;</span> <span class="nv">insanity</span> <span class="o">=</span> gets.chomp

  <span class="k">if</span> <span class="nv">insanity</span> <span class="o">==</span> <span class="s2">"1"</span> or <span class="nv">insanity</span> <span class="o">==</span> <span class="s2">"2"</span>
    puts <span class="s2">"Your body survives powered by a mind of jello.  Good job!"</span>
  <span class="k">else</span>
    puts <span class="s2">"The insanity rots your eyes into a pool of muck.  Good job!"</span>
  end

<span class="k">else</span>
  puts <span class="s2">"You stumble around and fall on a knife and die.  Good job!"</span>
end