Or, in J:

isleap=: 3 :'2|+/0=4 100 400|/y'

   isleap 1900 2000 2012 2100
0 1 1 0

(I am mentioning this because I think I included a buggy version of
this expression in an earlier message - I think I left out the 0=
part.)

Thanks,

-- 
Raul


On Mon, Sep 22, 2014 at 10:13 PM, Don Kelly <[email protected]> wrote:
> Fortunately, the use of "leap" is valid as long as one doesn't go back past
> 1901 or ahead past 2099.
>
> 1900 and 2100 aren't leap years (Fine tuning of the leap year calculation ).
>
> Don Kelly
>
>
>
>
> On 20/09/2014 10:53 PM, robert therriault wrote:
>>
>> Hi Linda,
>>
>> I share your dream and sometimes the statement 'I have a dream' can change
>> the world. :-)
>>
>> On to the weekend puzzle...
>>
>> The first thing I need to figure out is whether the birthday has happened
>> this year or not. If it has then I can pretty easily get the number of days
>> since the birthday using todayno, but if it hasn't then I need to find the
>> number of days since the previous year's birthday.
>>
>> 'yg mg dg' =: gbday =: 2002 2 2  NB. Groundhog's birthday
>> 'ya ma da'=:afterbday =: 2014 9 20      NB. An example of date after the
>> birthday
>> 'yb mb db'=:beforebday =: 2014 1 31      NB. An example of a date before
>> the birthday
>>
>> bdYet=:(0>-/) &: todayno  NB. returns 1 if the current date is in the same
>> calendar year before the birthday
>>     ya
>> 2014
>>     ya=. ya- afterbday bdYet ({. afterbday),}.gbday NB.use the current
>> year from example and the birthday
>>     ya
>> 2014
>>     yb
>> 2014
>>     yb=. yb- beforebday bdYet ({. beforebday),}.gbday
>>     yb
>> 2013
>>
>> Next thing would be to define a vector that gives the accumulated days in
>> the year if the year were to start on February 1st. The leap year issue
>> means that the first item in the list will be 29 if it is a leap year. since
>> I have already figured out whether I am counting from the previous year, I
>> will use the adjusted year to decide if the year that I am counting from was
>> a leap year. I will just use a simple (and incorrect) version of leap year.
>>
>> leap=: 0= 4&|
>> feb=: 28 + leap ya
>>     feb
>> 28
>>     [daysFebFirst=: +/\ (feb), 31 30 31 30 31 31 30 31 30 31 31
>> 28 59 89 120 150 181 212 242 273 303 334 365
>>
>> Finally, I create the results.
>>
>>     [yr=:ya-yg NB. number of years
>> 12
>>
>>     [elapsed=: -/ todayno"_1 afterbday,: ya,}.gbday NB. days since the
>> birthday
>> 230
>>     [mr=: +/ elapsed > daysFebFirst NB. number of months
>> 7
>>     [dr=: (<:mr){ elapsed - daysFebFirst
>> 18
>>     yr,mr,dr
>> 12 7 18
>>
>> And for the case of a date before the birthday Jan 31st 2014 we get
>>
>>     [feb=: 28 + leap yb NB. No change since 2013 is not a leap year
>> 28
>>     [yr=:yb-yg NB. number of years
>> 11
>>
>>     [elapsed=: -/ todayno"_1 beforebday ,: yb ,}.gbday NB. days since the
>> previous birthday
>> 363
>>     [mr=: +/ elapsed > daysFebFirst NB. number of months
>> 11
>>     [dr=: (<:mr){ elapsed - daysFebFirst
>> 29
>>     yr,mr,dr
>> 11 11 29
>>
>> Cheers, bob
>>
>> On Sep 20, 2014, at 10:58 AM, Linda Alvord <[email protected]>
>> wrote:
>>
>>> The J forum is my elementary school set of sub imjects.  What you suggest
>>> is
>>> exactly what I would hope would happen in a J classroom.  All would have
>>> J.
>>> All could experiment and exchange ideas. Hopefully they would have
>>> solutions
>>> they believe were correct.  Then they could explain their thinking to the
>>> entire class and the teacher.  At this point in the process, the teacher
>>> would not be a leader but a follower.
>>>
>>> Possibly I am dreaming....
>>>
>>> Linda
>>>
>>> -----Original Message-----
>>> From: [email protected]
>>> [mailto:[email protected]] On Behalf Of robert
>>> therriault
>>> Sent: Saturday, September 20, 2014 1:20 PM
>>> To: [email protected]
>>> Subject: Re: [Jprogramming] Weekend Puzzle - Age of Groundhog born 2002 2
>>> 2
>>>
>>> Hi Linda,
>>>
>>> If you are looking for a way to get learners to be interested in the
>>> problem, why not use the very model of learning that we are using here?
>>>
>>> You put a problem out to your class (forum) and see how the responses go.
>>> You as the teacher (moderator) are free to choose the rules, knowing that
>>> the students (participants) are able to put their attention elsewhere if
>>> things are not kept interesting. It is a style of learning that we use on
>>> these forums everyday and it seems to work for us.
>>>
>>> What might not work as well is going into the class and showing them how
>>> to
>>> solve the problem, as this takes away so much from the experience that we
>>> enjoy when we are learning. The challenge for the teacher is not so much
>>> coming up with a solution, as it is to make sure that they are engaging
>>> as
>>> many students as possible. This is especially true at the extremes of the
>>> class' abilities - both the really adept and those that are struggling
>>> with
>>> the concepts are where teachers are most valuable.
>>>
>>> Just my two bits, but I would probably just start with the question of
>>> 'how
>>> would you measure time in metric?' and use that as a way to explore all
>>> the
>>> ways that you would count and group the types of time and how they way we
>>> measure time can be pretty crazy and why it might be good if we could get
>>> computers to do the work of taking care of the crazy systems that we have
>>> set up. Where the class would take this in terms of topic is wide open,
>>> as a
>>> teacher you just make sure that as the core concepts arise they are
>>> covered
>>> accurately.
>>>
>>> Cheers, bob
>>>
>>> ps. The quickest way to get me to care about the age of your groundhog is
>>> to
>>> have one of my classmates start trying to figure it out, but my learning
>>> is
>>> usually socially motivated. :-)
>>>
>>> On Sep 20, 2014, at 9:35 AM, Joe Bogner <[email protected]> wrote:
>>>
>>>> Hi Linda
>>>>
>>>> The solution is quite simple and uses one built verb from an addon. I
>>>> posted it with the solution masked so others can try it on their own
>>>> without accidentally seeing mine
>>>>
>>>> The actual solution is the result of this:
>>>>
>>>> |. solution2
>>>> On Sep 20, 2014 11:54 AM, "Linda Alvord" <[email protected]>
>>>> wrote:
>>>>
>>>>> We are talking children here.
>>>>>
>>>>> Onyadot. emiTetaDot, ffiDst, onyadot, emiTetaDot, emitetad,  sepyt and
>>>>> eriuqer  are all denied!
>>>>>
>>>>> How about using +, -, *, ?, %: and that sort of thing.
>>>>>
>>>>> I must admit you did get  the right answer!
>>>>>
>>>>> You can also get a second chance.
>>>>>
>>>>> Cheers,  Linda
>>>>>
>>>>>
>>>>>
>>>>> -----Original Message-----
>>>>> From: [email protected]
>>>>> [mailto:[email protected]] On Behalf Of Joe
>>>
>>> Bogner
>>>>>
>>>>> Sent: Saturday, September 20, 2014 9:10 AM
>>>>> To: [email protected]
>>>>> Subject: Re: [Jprogramming] Weekend Puzzle - Age of Groundhog born 2002
>>>>> 2
>>>
>>> 2
>>>>>
>>>>> solution...
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> 1
>>>>> 2
>>>>> 3
>>>>> 4
>>>>> 5
>>>>>
>>>>>
>>>>> lightly obfuscated for someone who doesn't want the solution
>>>>>
>>>>>
>>>>> solution1=: 0 : 0
>>>>>
>>>>> )2 2 2002 onyadot emiTetaDot( ffiDst )02 9 4102 onyadot emiTetaDot(
>>>>>
>>>>> 'emitetad/sepyt' eriuqer
>>>>>
>>>>> )
>>>>>
>>>>>
>>>>>
>>>>> to run:
>>>>>
>>>>>
>>>>> 0!:1 |. solution1
>>>>>
>>>>>
>>>>>
>>>>> solution2 =: 0 : 0
>>>>>
>>>>> )2 2 2002( ffiDst )02 9 4102(
>>>>>
>>>>> 'emitetad/sepyt' eriuqer
>>>>>
>>>>> )
>>>>>
>>>>>
>>>>> 0!:1 |. solution2
>>>>>
>>>>>
>>>>>
>>>>> note: both take advantage of a addon. solution1 uses todayno just
>>>>> because
>>>>> it was stated in the problem but solution2 is what I'd really use
>>>>>
>>>>>
>>>>>
>>>>> On Sat, Sep 20, 2014 at 4:54 AM, Linda Alvord <[email protected]>
>>>>> wrote:
>>>>>
>>>>>> Using the verb  todayno  which provides the number of days since the
>>>>>> beginning of 1800,  write what you need to find the age today of a
>>>>>> groundhog
>>>>>> born on 2002 2 2.
>>>>>>
>>>>>>
>>>>>>
>>>>>>   todayno 2014 9 2014
>>>>>>
>>>>>> 80418
>>>>>>
>>>>>>
>>>>>>
>>>>>>   2014 9 20 age 2002 2 2
>>>>>>
>>>>>> 12 7 18
>>>>>>
>>>>>>
>>>>>>
>>>>>> His age is 12 years, 7 months and 18 days.  Use simple J.  Check that
>>>>>
>>>>> your
>>>>>>
>>>>>> solution provides a correct answer for you birthday.
>>>>>>
>>>>>>
>>>>>>
>>>>>> Have a pleasant weekend.
>>>>>>
>>>>>>
>>>>>>
>>>>>> Linda
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> ----------------------------------------------------------------------
>>>>>> For information about J forums see http://www.jsoftware.com/forums.htm
>>>>>>
>>>>> ----------------------------------------------------------------------
>>>>> For information about J forums see http://www.jsoftware.com/forums.htm
>>>>>
>>>>> ----------------------------------------------------------------------
>>>>> For information about J forums see http://www.jsoftware.com/forums.htm
>>>>>
>>>> ----------------------------------------------------------------------
>>>> For information about J forums see http://www.jsoftware.com/forums.htm
>>>
>>> ----------------------------------------------------------------------
>>> For information about J forums see http://www.jsoftware.com/forums.htm
>>>
>>> ----------------------------------------------------------------------
>>> For information about J forums see http://www.jsoftware.com/forums.htm
>>
>> ----------------------------------------------------------------------
>> For information about J forums see http://www.jsoftware.com/forums.htm
>>
>
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm

Reply via email to