ruby学习编程示例8混淆

Question

新来的红宝石，提前道歉。我挣扎于这个例子，从一个学习到程序教程。我仍然不知道“写”到底是什么意思-- ..is --它是输入数字除以100？如果是这样的话，write>0如何返回100。如果有人能够至少清楚地解释这个例子的第一部分，那将非常有帮助。

We'll call this one englishNumber. It will take a number, like 22, and return the english version of it (in this case, the string 'twenty-two'). For now, let's have it only work on integers from 0 to 100.


def englishNumber number
  # We only want numbers from 0-100.
  if number < 0
    return 'Please enter a number zero or greater.'
  end
  if number > 100
    return 'Please enter a number 100 or lesser.'
  end

  numString = ''  # This is the string we will return.

  # "left" is how much of the number we still have left to write out.
  # "write" is the part we are writing out right now.
  # write and left... get it?  :)
  left  = number
  write = left/100          # How many hundreds left to write out?
  left  = left - write*100  # Subtract off those hundreds.

  if write > 0
    return 'one hundred'
  end

  write = left/10          # How many tens left to write out?
  left  = left - write*10  # Subtract off those tens.

  if write > 0
    if write == 1  # Uh-oh...
      # Since we can't write "tenty-two" instead of "twelve",
      # we have to make a special exception for these.
      if    left == 0
        numString = numString + 'ten'
      elsif left == 1
        numString = numString + 'eleven'
      elsif left == 2
        numString = numString + 'twelve'
      elsif left == 3
        numString = numString + 'thirteen'
      elsif left == 4
        numString = numString + 'fourteen'
      elsif left == 5
        numString = numString + 'fifteen'
      elsif left == 6
        numString = numString + 'sixteen'
      elsif left == 7
        numString = numString + 'seventeen'
      elsif left == 8
        numString = numString + 'eighteen'
      elsif left == 9
        numString = numString + 'nineteen'
      end
      # Since we took care of the digit in the ones place already,
      # we have nothing left to write.
      left = 0
    elsif write == 2
      numString = numString + 'twenty'
    elsif write == 3
      numString = numString + 'thirty'
    elsif write == 4
      numString = numString + 'forty'
    elsif write == 5
      numString = numString + 'fifty'
    elsif write == 6
      numString = numString + 'sixty'
    elsif write == 7
      numString = numString + 'seventy'
    elsif write == 8
      numString = numString + 'eighty'
    elsif write == 9
      numString = numString + 'ninety'
    end

    if left > 0
      numString = numString + '-'
    end
  end

  write = left  # How many ones left to write out?
  left  = 0     # Subtract off those ones.

  if write > 0
    if    write == 1
      numString = numString + 'one'
    elsif write == 2
      numString = numString + 'two'
    elsif write == 3
      numString = numString + 'three'
    elsif write == 4
      numString = numString + 'four'
    elsif write == 5
      numString = numString + 'five'
    elsif write == 6
      numString = numString + 'six'
    elsif write == 7
      numString = numString + 'seven'
    elsif write == 8
      numString = numString + 'eight'
    elsif write == 9
      numString = numString + 'nine'
    end
  end

  if numString == ''
    # The only way "numString" could be empty is if
    # "number" is 0.
    return 'zero'
  end

  # If we got this far, then we had a number somewhere
  # in between 0 and 100, so we need to return "numString".
  numString
end

puts englishNumber(  0)
puts englishNumber(  9)
puts englishNumber( 10)
puts englishNumber( 11)
puts englishNumber( 17)
puts englishNumber( 32)
puts englishNumber( 88)
puts englishNumber( 99)
puts englishNumber(100)

Answer 1

这是因为left / 100正在执行名为整数除法的操作。这实际上是除以100，然后丢弃分数。因此，例如：

left = 138
write = left / 100
puts write #=> 1

如果你在计算器上这样做，你会得到1.38。如果你去掉小数位，剩下的是1。这是一种简单的方法，可以确定一个数字中有多少个数字。

所以在你的例子中，如果数字大于100，那么write > 0 -程序将打印‘100’

顺便提一句，测试这些内容的一个很好的技巧是，如果您输入Ruby解释器(在控制台中输入ruby )，然后在Ruby中键入这些命令，就会打印出答案。