70 lines
2.9 KiB
HTML
70 lines
2.9 KiB
HTML
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
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"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<html>
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<head>
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<title>i231.fraction.v2</title>
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</head>
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<body>
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Write an implementation (class <code>Lfraction</code>) for an abstract data
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type "Fraction", where the fraction consists of two long integers:
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numerator and denominator. Always convert
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fractions to a form, where denominator is strictly positive and
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the fraction is reduced. By default all operations (described on webpage
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http://www.itcollege.ee/~jpoial/algoritmid/Lfraction/index.html ) must be exact
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and use integer arithmetics only (e.g. do not use floating point arithmetics
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to compare two fractions).
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<br><br>
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Remark 1. In addition to public methods listed you may need
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a method to find the greatest common divisor of two integers to reduce
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the fractions.
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<br>
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Remark 2. Operations must not modify operands, a new fraction must be
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created for the result.
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<br>
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Remark 3. Methods <code>toString</code> and <code>valueOf</code> must
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be dual: method <code>valueOf</code> must be able to interpret all
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strings generated by the method <code>toString</code> .
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<br>
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Remark 4. If an error occurs (division by zero, illegal string, etc.)
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the program must throw an exception of class <code>RuntimeException</code>
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(or any appropriate subclass of <code>RuntimeException</code>).
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<br>
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Remark 5. Sign of a fraction is in numerator and integer numbers
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expressed as fractions must have denominator 1, e.g.
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3 is 3/1 , -5 is (-5)/1 and 0 is 0/1 .
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<br><br>
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Realiseerida abstraktne andmetüüp "murd pikkade täisarvude paarina".
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<br>
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Murdu esindab objekt klassist <code>Lfraction</code>, mis sisaldab murru
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lugejat (ingl.k. numerator) ja murru nimetajat (ingl.k. denominator)
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pikkade täisarvudena (teha nii, et nimetaja oleks alati rangelt positiivne
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ning murd taandatud).
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<br>
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Realiseerida kõik operatsioonid, mis on kirjeldatud programmitoorikus (ja
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veebilehel http://www.itcollege.ee/~jpoial/algoritmid/Lfraction/index.html ).
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Murdude võrdlus peab olema täpne, s.t. toetuma arvutustele täisarvudega,
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mitte reaalarvuliste lähiväärtustega.
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<br><br>
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Märkus 1. Lisaks loetletud avalikele meetoditele on teil tõenäoliselt
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tarvis murru taandamise meetodit ja võib-olla ka kahe täisarvu
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suurima ühisteguri leidmise meetodit.
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<br>
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Märkus 2. Reeglina ei tohi meetodid muuta objekti, millele neid rakendatakse
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(näit. liitmisel ei tohi muuta liidetavaid, tuleb summa jaoks luua uus murd).
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<br>
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Märkus 3. Sõne teisendamisel murruks peab <code>valueOf</code>-meetod
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olema kooskõlas <code>toString</code>-meetodiga (peab oskama tõlgendada
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niisugust sõnet, mida <code>toString</code> tagastab).
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<br>
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Märkus 4. Veasituatsioonid (sõne, mida ei saa teisendada; nulliga jagamine
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jt.) peavad tekitama erindi klassist <code>RuntimeException</code> või mõnest
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selle klassi sobivast alamklassist.
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<br>
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Märkus 5. Murru märk käib lugeja juurde ning täisarvude nimetaja on 1 (ka
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arvu 0 puhul).
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<br><br>
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</body>
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</html>
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