输入与Module

ruby的输入

print "How old are you? "
age = gets.chomp()
print "How tall are you? "
height = gets.chomp()
print "How much do you weigh? "
weight = gets.chomp()

puts "So, you're #{age} old, #{height} tall and #{weight} heavy."

为什么使用的的print 而非 puts ？ print不会产生新行，puts会产生新行

---

 str.chomp(separator=$/) → new_str

Returns a new String with the given record separator removed from the end of str (if present). If $/ has not been changed from the default Ruby record separator, then chomp also removes carriage return characters (that is it will remove \n, \r, and \r\n). If $/ is an empty string, it will remove all trailing newlines from the string.

Module

require 'open-uri'

open("http://www.ruby-lang.org/en") do |f|
  f.each_line {|line| p line}
  puts f.base_uri         # <URI::HTTP:0x40e6ef2 URL:http://www.ruby-lang.org/en/>
  puts f.content_type     # "text/html"
  puts f.charset          # "iso-8859-1"
  puts f.content_encoding # []
  puts f.last_modified    # Thu Dec 05 02:45:02 UTC 2002
end

require 与 include

require：类似于 C 和 C++ 中的 include 语句以及 Java 中的 import 语句。如果一个第三方的程序想要使用任何已定义的模块，则可以简单地使用 Ruby require 语句来加载模块文件：

require filename

include : 可以在类中嵌入模块。如果是模块是单独定义在一个单独的文件中，那么在嵌入模块之前就需要使用require语句引用该文件

class Decade
include Week
   no_of_yrs=10
   def no_of_months
      puts Week::FIRST_DAY
      number=10*12
      puts number
   end
end
d1=Decade.new
puts Week::FIRST_DAY
Week.weeks_in_month
Week.weeks_in_year
d1.no_of_months


module Week
   FIRST_DAY = "Sunday"
   def Week.weeks_in_month
      puts "You have four weeks in a month"
   end
   def Week.weeks_in_year
      puts "You have 52 weeks in a year"
   end
end

Ruby中的Mixins

Ruby 不直接支持多重继承，但是 Ruby 的模块（Module）有另一个神奇的功能。它几乎消除了多重继承的需要，提供了一种名为 mixin 的装置。
Ruby 没有真正实现多重继承机制，而是采用成为mixin技术作为替代品。将模块include到类定义中，模块中的方法就mix进了类中。

module A
   def a1
   end
   def a2
   end
end
module B
   def b1
   end
   def b2
   end
end

class Sample
include A
include B
   def s1
   end
end

samp=Sample.new
samp.a1
samp.a2
samp.b1
samp.b2
samp.s1