From: Robert Klemme <shortcutter@...>
Date: 2011-08-16T00:16:46+09:00
Subject: Re: A Corresponding between C++ AND Ruby

On Fri, Aug 12, 2011 at 6:35 PM, David Masover <ninja@slaphack.com> wrote:
> On Friday, August 12, 2011 09:02:36 AM Dave Baldwin wrote:
>> On 12 Aug 2011, at 14:10, amir a. wrote:
>> > 2 - int a,b,c,d;
>> >
>> >    while( 1 ) {
>> >
>> >       cin >> a >> b >> c >>d ;
>> >       if( a < 0 || b < 0 )
>> >
>> >          break;
>> >
>> >       cout << a << " " << b << " " << c << " " << d << endl;
>> >
>> >    }
>>
>> while true
>>       a, b, c, d = gets.split.map {|s| s.to_i}
>>       break if a < 0 || b < 0
>>       STDOUT << a << " " << b << " " << c << " " << d << "\n";
>> end
>
> A nitpick: This doesn't do exactly the same thing. The 'cin' version, if I
> understand it, will read the next four things which look like integers,
> separated by any whitespace, including newlines. It only seems like it
> operates per-line since that's how you'd manually enter text into stdin, but
> the program actually sees it as an unbroken stream. So you can enter each
> number on its own line, or eight of them on the same line...
>
> The gets version will read a single line. If there aren't enough integers,
> some variables will be nil. If there are too many, some integers will be
> ignored, not carried over to the next line.

This can be fixed with a construction similar to this

$ ruby19 -e 'n=[];loop do while(n.size <
4);n.concat(gets.scan(/\d+/).map(&:to_i)) end;a=n.slice!(0,4); p a;
end'
1 2
3
4 5 6
[1, 2, 3, 4]
7

8
[5, 6, 7, 8]
6
 5 4 3 2 1
[6, 5, 4, 3]
0
1
[2, 1, 0, 1]
-e:1:in `block in <main>': undefined method `scan' for nil:NilClass
(NoMethodError)
        from -e:1:in `loop'
        from -e:1:in `<main>'

:-)

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/