[Neworleans-pm] Fwd: Perl Quiz-of-the-Week #19

[Brett D. Estrade]

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----- Original message -----
From: "Belden Lyman" <blyman at iii.com>
To: perl-qotw at plover.com
Date: Wed, 07 Jul 2004 12:49:53 -0400
Subject: Perl Quiz-of-the-Week #19


IMPORTANT: Please do not post solutions, hints, or other spoilers
        until at least 60 hours after the date of this message.
        Thanks.

IMPORTANTE: Por favor, no enviéis soluciones, pistas, o cualquier otra
        cosa que pueda echar a perder la resolución del problema hasta
        que hayan pasado por lo menos 60 horas desde el envío de este
        mensaje. Gracias.

IMPORTANT: S'il vous plaît, attendez au minimum 60 heures après la
        date de ce message avant de poster solutions, indices ou autres
        révélations. Merci.

WICHTIG: Bitte schicken Sie keine Lösungen, Tipps oder Hinweise für
        diese Aufgabe vor Ablauf von 60 Stunden nach dem Datum dieser
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BELANGRIJK: Stuur aub geen oplossingen, hints of andere tips in de
        eerste 60 uur na het verzendingstijdstip van dit
        bericht. Waarvoor dank.

VNIMANIE: Pozhalujsta ne shlite reshenija, nameki na reshenija, i
        voobshe lyubye podskazki v techenie po krajnej mere 60 chasov
        ot daty etogo soobshenija.  Spasibo.

Qing3 Zhu4Yi4: Qing3 Ning2 Deng3Dao4 Jie1Dao4 Ben3 Xin4Xi2 Zhi1Hou4 60
        Xiao3Shi2, Zai4 Fa1Biao3 Jie3Da2, Ti2Shi4, Huo4 Qi2Ta1 Hui4
        Xie4Lou4 Da2An4 De5 Jian4Yi4.  Xie4Xie4.

----------------------------------------------------------------

When you think of a sailing vessel, chances are good that you think
of a bermudan rig, which has two triangular sails arranged like this:

                           |*
			   | *
                           |  *
                           |   *
                          *|    *
                         * |     *
                        *  |      *
                       *   |       *
                      *    |        *
                     *     |         *
                    *      |          *
                   *       |           *
                  *        |            *
                 *         |             *
                *          |  mainsail    *
               *   jib     |               *
              *            |________________*
             *             |             
             --------------|
            ,--------------|------------------.
   front     \                               /   back
              \_____________________________/

                (A bermudan-rigged vessel)


If you've ever seen a Chinese junk, a Norse longboat, or a Polynesian
sailing outrigger, then you know that there are many other sail shapes.
For example, many popular small sailing dinghies use a lateen sail
because it is easy for a single person to manage. Notice the lack of
right angles:


                     |     /\
                     |   ,/  \.
                     |  /'    `\
                     |,/        \.
                     /'          `\
                   ,/              \.
                  /'    lateen      `\ 
                ,/      mainsail      \. 
               /'                      `\ 
              /                          \
              ---------------------------- 
                     |
            ,--------|------------------------.
   front     \                               /   back
              \_____________________________/
                (A lateen-rigged vessel)

Finally, there are non-triangular sails, such as a gaff-rigged sail.
These look similar to a triangular bermudan mainsail, but have an
extra boom (the "gaff") at the *top* of the sail:

                   gaff--> /*
                          /  *  
                        |/    *
                        |      *     
                        |       *     
                        |        *     
                        |         *     
                        |          *     
                        |           *     
                        |            *     
                        |             *     
                        |              *     
                        |  gaffed       *     
                        |  mainsail      *     
                        |                 *     
                        |__________________*
                        |     
                        |     
            ,-----------|--------------------.
   front     \                               /   back
              \_____________________________/

                   (A gaff-rigged vessel)

You will write a program, sailarea.pl, capable of calculating the
sail area of triangular and gaff-rigged sails. The program is run
as follows:

      sailarea.pl filename [scale]
      
Scale, if given, is a percentage by which to increase or decrease the
calculated sail area. If not given, scale defaults to 100% (no scaling).

The input file contains the coordinates of each sail in the sailplan;
units are implied to be in centimeters. Blank and commented lines are
valid.

      sailname.a: x,y
      sailname.b: x,y
      sailname.c: x,y

      anothersail.a: x,y
      anothersail.b: x,y
      anothersail.c: x,y

The various sail shapes cannot be intuited from 'sailname'. 'sailname'
exists only as a tag to associate various points with a single sail.
Assume that the sail is gaff-rigged if it has four coordinates, and
triangular if it has only three.

For example, given bermudan.txt:

      # coordinates for a bermudan rig
      mainsail.a: 0, 450
      mainsail.b: 0, 50
      mainsail.c: 200, 50

      jib.a: 0,400
      jib.b: 150,0
      jib.c: 0,0

When run as

     sailarea.pl bermudan.txt

the program responds with individual sail areas and the total sail
area:

     mainsail.area: 40000 cm^2
     jib.area: 30000 cm^2
     total.area: 70000 cm^2