From: Josh Cheek <josh.cheek@...>
Date: 2011-04-24T03:33:16+09:00
Subject: Re: Reversing a string without using array, classes and reverse function

--90e6ba53ac2e19075704a19a35af
Content-Type: text/plain; charset=ISO-8859-1

On Thu, Apr 21, 2011 at 10:54 PM, Rubist Rohit <
passionate_programmer@hotmail.com> wrote:

> I am trying this:
>
> mystring = gets
> mystring.scan(/..$/) {|x| puts x}
>
> It returns only the last character. Is it possible to add the above line
> in loop?
>
> --
> Posted via http://www.ruby-forum.com/.
>
>
Thought I'd join the fun :)


s = "12345"

# using reverse
s.reverse # => "54321"


# using each_char
s2 = ""
s.each_char { |char| s2 = char << s2 }
s2 # => "54321"


# using scan
s2 = ""
s.scan(/./) { |char| s2 = char << s2 }
s2 # => "54321"


# using unix (this doesn't escape all chars properly, though)
`rev <<<#{s.inspect}`.chomp # => "54321"


# using recursion
rev = lambda do |string|
  if string.empty?
    ""
  else
    rev.call(string[1..-1]) << string[0,1]
  end
end
rev.call s # => "54321"


# exchanging chars
s2 = s.dup
s2.length./(2).times { |i| s2[i] , s2[-i-1] = s2[-i-1] , s2[i] }
s2 # => "54321"

--90e6ba53ac2e19075704a19a35af--