233 lines
12 KiB
HTML
233 lines
12 KiB
HTML
<!DOCTYPE doctype PUBLIC "-//w3c//dtd html 4.0 transitional//en">
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
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<meta name="GENERATOR" content="Mozilla/4.76 [en] (Win98; U)
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[Netscape]">
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<title>API kordamine</title>
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</head>
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<body>
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<h2 style="margin-left: 40px;">Java API<br>
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</h2>
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<div style="margin-left: 40px;">This lab is for practicing Java -
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you have to find descriptions of the following classes and solve a
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set of small problems.<br>
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</div>
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<p style="margin-left: 40px;"><tt>java.lang.String</tt> <br>
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<tt>java.lang.StringBuffer/StringBuilder<br>
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java.lang.Character</tt> <br>
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<tt>java.lang.Integer (-> Double, ...)</tt> <br>
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<tt>java.lang.Math</tt> <br>
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<tt>java.lang.Comparable</tt> </p>
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<p style="margin-left: 40px;"><tt>java.util.StringTokenizer</tt> <tt><br>
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java.util.Calendar</tt><br>
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<tt>java.util.Random</tt> <tt><br>
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java.util.ArrayList</tt> <tt><br>
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java.util.HashMap</tt><br>
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<span style="font-family: monospace;">java.util.Set</span><br>
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<tt>java.util.List<br>
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java.util.Collection<br>
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java.util.TreeSet<br>
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</tt><tt>java.util.Arrays<br>
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java.util.Iterator<br>
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</tt></p>
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<p style="margin-left: 40px;">...<br>
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</p>
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<h3 style="margin-left: 40px;">Problems</h3>
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<div style="margin-left: 40px;">
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<ul>
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<li>Convert a given double number (<span style="font-family:
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monospace;">double</span>) into String (<span
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style="font-family: monospace;">String</span>).</li>
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<li>Convert a string (<span style="font-family: monospace;">String</span>)
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into an integer number (<span style="font-family: monospace;">int</span>).
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Assume that the string actually represents an integer
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(Discover what happens, if the string is illegal?).</li>
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<li>Take the current moment of time from the computers inner
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clock and form a string "hours:minutes:seconds" (use 24h
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notation, e.g. "13:25:10").</li>
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<li>Find a cosine of a given angle that is expressed in degrees.</li>
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<li>Print a table of square roots for numbers from 0 up to 100
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using step 5 (print two numbers per line: argument and its
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square root).</li>
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<li>Given a string replace in it all uppercase letters with
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corresponding lowercase letters and all lowercase letters with
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corresponding uppercase letters. Do not change other symbols (<span
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style="font-family: monospace;">"ABcd12"</span> -> <span
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style="font-family: monospace;">"abCD12"</span>). Use <span
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style="font-family: monospace;">StringBuffer</span> or <span
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style="font-family: monospace;">StringBuilder</span> class
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for intermediate result. Create an independent method <code
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id="yui_3_2_0_1_1314010804247640">String reverseCase (String
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s) </code>for this task.</li>
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<li>Given a string find its reverse (<span style="font-family:
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monospace;">"1234ab"</span> -> <span style="font-family:
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monospace;">"ba4321"</span>).</li>
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<li>Given a text (<span style="font-family: monospace;">String</span>)
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find the number of words in it. Words are separated by any
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positive number of any kind of whitespaces (like space, tab,
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...). Create an independent method <code>int countWords
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(String t) </code>for this task.</li>
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<li>Register the current time, pause the program for 3 seconds,
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register the current time again and print the difference
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between these two moments of time in milliseconds.</li>
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<li>Create a list (<span style="font-family: monospace;">ArrayList</span>)
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of 100 random integers (<span style="font-family: monospace;">Integer</span>)
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in between 0 and 999. Print the result. What is the difference
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between<span style="font-family: monospace;"> int </span>and
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<span style="font-family: monospace;">Integer</span>?</li>
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<li>Find the minimal element of this list. How to find the
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minimal element of any <span style="font-family: monospace;">List</span>
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of <span style="font-family: monospace;">Comparable</span>
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elements (read about interfaces, also consider that <span
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style="font-family: monospace;">ArrayList implements List </span>and
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<span style="font-family: monospace;">Integer implements
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Comparable</span>)?</li>
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<li>Create a hashtable (<span style="font-family: monospace;">HashMap</span>)
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containing 5 pairs of strings, where "subject code" serves as
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a key and "subject name" serves as a value (e.g. <span
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style="font-style: italic;">("I231", "Algorithms and Data
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Structures")</span> , just choose any subjects you like).</li>
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<li>Print all the keys of this hashtable (one key per line).</li>
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<li>Remove one of the subjects from the hashtable.</li>
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<li>Print all pairs from this hashtable (each pair on separate
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line).</li>
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<li>Reverse the order of elements of the list you have created
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before. Write an independent method<code> </code>to reverse
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any list. The method signature is</li>
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</ul>
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<div style="margin-left: 80px;"><span style="font-family:
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monospace;">public static <T extends Object> void
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reverseList (List<T> list)</span><br style="font-family:
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monospace;">
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<span style="font-family: monospace;">
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throws UnsupportedOperationException </span><br>
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</div>
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</div>
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<div style="margin-left: 40px;"><br>
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<div style="margin-left: 40px;">Output the result and check that
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it is correct.<br>
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</div>
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</div>
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<div style="margin-left: 40px;">
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<ul>
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<li>Write an independent method to find the maximal element of
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any Java collection (you can use your list for testing). The
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method signature is</li>
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</ul>
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<div style="margin-left: 40px;">
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<div style="margin-left: 40px;"><span style="font-family:
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monospace;">static public <T extends Object &
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Comparable<? super T>> T</span> <span
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style="font-family: monospace;">maximum (Collection<?
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extends T> a) </span><br>
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<span style="font-family: monospace;">
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throws NoSuchElementException</span><br>
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</div>
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</div>
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<br>
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You have to upload your full solution to <a
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href="https://moodle.hitsa.ee/">Moodle</a> !<br>
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<br>
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Git repository address: <a
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href="https://jpoial@bitbucket.org/i231/lab1.git">https://jpoial@bitbucket.org/i231/lab1.git</a><br>
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</div>
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<div style="margin-left: 40px;"> <br>
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<hr style="width: 100%; height: 2px;"></div>
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<h3 style="margin-left: 40px;">Oskused, mis tuleks praktikumide
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käigus omandada:</h3>
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<ul style="margin-left: 40px;">
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<li>informatsiooni kiire leidmine API kirjeldusest </li>
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<li>teisendused ühest tüübist teise, mähisklasside kasutamine</li>
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<li> lihtsate arvutuste tegemine</li>
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<li> sõnetöötlus, sõnepuhvri kasutamine</li>
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<li> aega väljendavate andmetega manipuleerimine</li>
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<li> juhuslike andmete genereerimine</li>
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<li> listi ja paisktabeli kasutamine, iteraatorid</li>
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</ul>
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<h3 style="margin-left: 40px;"> Ülesanded:</h3>
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<div style="margin-left: 40px;">Koostage peameetod (<tt>main</tt>),
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mis sisaldaks lahendust järgmistele probleemidele: </div>
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<ul style="margin-left: 40px;">
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<li> Teisendada etteantud reaalarv (<span
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style="font-family: monospace;">double</span>) sõneks (<tt>String</tt>).</li>
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<li> Teisendada etteantud sõne täisarvuks (eeldusel, et see
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sõne väljendab täisarvu).</li>
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<li> Võtta arvuti kellalt jooksev näit ning moodustada sõne
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kujul: <i>tunnid:minutid:sekundid </i>(tunnid 24h skaalal).</li>
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<li> Leida kraadides etteantud nurga koosinus.</li>
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<li> Väljastada ruutjuurte tabel arvude 0 kuni 100 jaoks
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sammuga 5.</li>
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<li> Vahetada etteantud sõnes suurtähed väiketähtedega ja
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vastupidi jättes muud sümbolid muutmata (<span
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style="font-family: monospace;">"ABcd12"</span> -> <span
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style="font-family: monospace;">"abCD12"</span>). Kasutage
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vahetulemuste salvestamiseks sõnepuhvrit (<tt>StringBuffer</tt>).</li>
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<li> Muuta etteantud sõne sümbolite järjekord vastupidiseks
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(<span style="font-family: monospace;">"1234ab"</span> -> <span
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style="font-family: monospace;">"ba4321"</span>).</li>
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<li> Leida sõnade arv etteantud sõnes (sõnade eraldajaks
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olgu vähemalt üks tühik, tabulatsioonimärk vms).</li>
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<li> Võtta arvuti kellalt jooksev aeg, teha etteantud
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pikkusega paus (näiteks 3 sek.), võtta uuesti jooksev aeg ning
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arvutada nende kahe ajahetke tegelik vahe millisekundites.<br>
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</li>
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</ul>
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<ul style="margin-left: 40px;">
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<li> Genereerida juhuarvudest vahemikus 0 kuni 999 (<tt>Integer</tt>)
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koosnev 100-elemendiline list (<tt>ArrayList</tt>) ning
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väljastada see.</li>
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<li> Leida selle listi vähim element. Proovige kirjutada
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eraldi meetod, mis leiaks etteantud <tt>List</tt>-liidest
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rahuldava objekti vähima elemendi eeldusel, et elemendid on
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võrreldavad liidese <tt>Comparable</tt> mõttes (mida <tt>Integer</tt>
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isendid ka on).</li>
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<li> Moodustada paisktabel (<tt>HashMap</tt>) umbes 5
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elemendiga, milles võtmeks on õppeaine kood (<tt>String</tt>) ja
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elemendiks õppeaine nimetus (<tt>String</tt>). Andmed mõelge ise
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välja.<br>
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</li>
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<li> Väljastada selle paisktabeli kõik võtmed.</li>
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<li> Eemaldada üks ainetest sellest tabelist.</li>
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<li> Väljastada kõik paarid "võti - väärtus" sellest tabelist.</li>
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<li> Muuta esimeses ülesandes genereeritud listi (<span
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style="font-family: monospace;">ArrayList</span>) elementide
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järjekord vastupidiseks. Väljastada tulemus ja kontrollida selle
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õigsust.</li>
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<li> Koostada maksimumi leidmise meetod (eraldi meetodina), mis
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kasutaks liideseid <tt>Collection</tt> ja <tt>Comparable</tt>
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(s.t. meetodi parameetriks on <span style="font-family:
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monospace;">Collection</span>-objekt, mis sisaldab <span
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style="font-family: monospace;">Comparable</span>-liidest
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rahuldavaid elemente, meetodi tagastusväärtuseks on maksimaalne
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element <span style="font-family: monospace;">Comparable</span>-tüüpi
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objektina). Selle meetodi poole pöördumisel võite kasutada
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esimeses ülesandes loodud listi.<br>
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</li>
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</ul>
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<ul style="margin-left: 40px;">
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</ul>
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<div style="margin-left: 40px;">
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<div style="margin-left: 40px;"><span style="font-weight: bold;"></span>Programm testida ja
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esitada Moodle kaudu.<br>
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<br>
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Git repositoorium: <a
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href="https://jpoial@bitbucket.org/i231/lab1.git">https://jpoial@bitbucket.org/i231/lab1.git<br>
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</a><br>
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</div>
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<br>
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<hr style="width: 100%; height: 2px;">Jaanus Pöial<br>
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<br>
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<br>
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<br>
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<br>
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</div>
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</body>
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</html>
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