<?xml version="1.0" encoding="utf-8"?><!DOCTYPE article  PUBLIC '-//OASIS//DTD DocBook XML V4.4//EN'  'http://www.docbook.org/xml/4.4/docbookx.dtd'><article><articleinfo><title>変数の宣言と初期化</title><revhistory><revision><revnumber>20</revnumber><date>2011-09-20 03:51:20</date><authorinitials>masahiko</authorinitials></revision><revision><revnumber>19</revnumber><date>2011-09-20 03:45:53</date><authorinitials>masahiko</authorinitials></revision><revision><revnumber>18</revnumber><date>2011-09-20 02:45:50</date><authorinitials>masahiko</authorinitials></revision><revision><revnumber>17</revnumber><date>2011-09-20 02:43:44</date><authorinitials>masahiko</authorinitials></revision><revision><revnumber>16</revnumber><date>2010-10-07 11:44:46</date><authorinitials>masahiko</authorinitials></revision><revision><revnumber>15</revnumber><date>2009-10-06 11:54:47</date><authorinitials>masahiko</authorinitials></revision><revision><revnumber>14</revnumber><date>2009-10-02 12:25:22</date><authorinitials>masahiko</authorinitials></revision><revision><revnumber>13</revnumber><date>2009-10-02 12:24:06</date><authorinitials>masahiko</authorinitials></revision><revision><revnumber>12</revnumber><date>2009-10-02 12:22:24</date><authorinitials>masahiko</authorinitials></revision><revision><revnumber>11</revnumber><date>2009-10-02 12:21:56</date><authorinitials>masahiko</authorinitials></revision><revision><revnumber>10</revnumber><date>2009-10-02 12:21:39</date><authorinitials>masahiko</authorinitials></revision><revision><revnumber>9</revnumber><date>2009-09-30 11:36:34</date><authorinitials>masahiko</authorinitials></revision><revision><revnumber>8</revnumber><date>2009-09-30 11:34:14</date><authorinitials>masahiko</authorinitials></revision><revision><revnumber>7</revnumber><date>2008-10-28 00:33:14</date><authorinitials>masahiko</authorinitials></revision><revision><revnumber>6</revnumber><date>2008-10-27 01:22:32</date><authorinitials>masahiko</authorinitials></revision><revision><revnumber>5</revnumber><date>2008-10-25 01:00:19</date><authorinitials>masahiko</authorinitials></revision><revision><revnumber>4</revnumber><date>2008-10-24 12:19:32</date><authorinitials>masahiko</authorinitials></revision><revision><revnumber>3</revnumber><date>2008-10-24 12:06:55</date><authorinitials>masahiko</authorinitials></revision><revision><revnumber>2</revnumber><date>2008-10-23 06:43:00</date><authorinitials>masahiko</authorinitials></revision><revision><revnumber>1</revnumber><date>2008-10-23 06:39:55</date><authorinitials>masahiko</authorinitials></revision></revhistory></articleinfo><section><title>変数の宣言と初期化</title><!--rule (<hr>) is not applicable to DocBook--><section><title>変数の宣言</title><para>変数の宣言は次のような形式で行ないます。 </para><itemizedlist><listitem override="none"><para><inlinemediaobject><imageobject><imagedata fileref="http://ei-www.hyogo-dai.ac.jp/~masahiko/moin.cgi/%E5%A4%89%E6%95%B0%E3%81%AE%E5%AE%A3%E8%A8%80%E3%81%A8%E5%88%9D%E6%9C%9F%E5%8C%96?action=AttachFile&amp;do=get&amp;target=hensu1.png"/></imageobject><textobject><phrase>hensu1.png</phrase></textobject></inlinemediaobject> </para></listitem></itemizedlist><para>例 </para><itemizedlist><listitem override="none"><programlisting format="linespecific" language="java" linenumbering="numbered" startinglinenumber="1"><![CDATA[ ]]><token><![CDATA[int]]></token><![CDATA[ ]]><methodname><![CDATA[kosu]]></methodname><![CDATA[;]]>
<![CDATA[ ]]><token><![CDATA[double]]></token><![CDATA[ ]]><methodname><![CDATA[x]]></methodname><![CDATA[, ]]><methodname><![CDATA[y]]></methodname><![CDATA[;]]>
</programlisting></listitem></itemizedlist><!--rule (<hr>) is not applicable to DocBook--></section></section><section><title>宣言と同時に変数を初期化</title><para>変数の宣言と初期化の構文は次のようになります。 </para><itemizedlist><listitem override="none"><para><inlinemediaobject><imageobject><imagedata fileref="http://ei-www.hyogo-dai.ac.jp/~masahiko/moin.cgi/%E5%A4%89%E6%95%B0%E3%81%AE%E5%AE%A3%E8%A8%80%E3%81%A8%E5%88%9D%E6%9C%9F%E5%8C%96?action=AttachFile&amp;do=get&amp;target=hensu6.png"/></imageobject><textobject><phrase>hensu6.png</phrase></textobject></inlinemediaobject> </para></listitem></itemizedlist><para>１つの変数を宣言した後ろに、 代入文が続いた形をしています。 </para><para>代入文の前に<emphasis role="strong">型</emphasis>が書かれた形と考えても良い。 </para><para>参考 (代入文の構文) </para><itemizedlist><listitem override="none"><para><inlinemediaobject><imageobject><imagedata fileref="http://ei-www.hyogo-dai.ac.jp/~masahiko/moin.cgi/%E5%A4%89%E6%95%B0%E3%81%AE%E5%AE%A3%E8%A8%80%E3%81%A8%E5%88%9D%E6%9C%9F%E5%8C%96?action=AttachFile&amp;do=get&amp;target=koubun04.png"/></imageobject><textobject><phrase>koubun04.png</phrase></textobject></inlinemediaobject> </para></listitem></itemizedlist><para>例 </para><itemizedlist><listitem override="none"><programlisting format="linespecific" language="java" linenumbering="numbered" startinglinenumber="1"><![CDATA[ ]]><token><![CDATA[int]]></token><![CDATA[ ]]><methodname><![CDATA[k]]></methodname><![CDATA[ = 1000;]]>
</programlisting></listitem></itemizedlist><para>これは次と同じ意味。 </para><itemizedlist><listitem override="none"><programlisting format="linespecific" language="java" linenumbering="numbered" startinglinenumber="1"><![CDATA[ ]]><token><![CDATA[int]]></token><![CDATA[ ]]><methodname><![CDATA[k]]></methodname><![CDATA[;]]>
<![CDATA[ ]]><methodname><![CDATA[k]]></methodname><![CDATA[ = 1000;]]>
</programlisting></listitem></itemizedlist><!--rule (<hr>) is not applicable to DocBook--><section><title>ブロック内での変数宣言</title><para>変数の宣言は 通常はメソッドの先頭や、クラスの先頭で行います。 </para><para>途中の命令文が書ける位置に書くこともできます。 </para><para>ブロック内で宣言すると、 その変数は宣言したブロック内でしか使えません。 </para><para>for文でくりかえしのためにつかう変数をその場で宣言する ことができます。 </para><itemizedlist><listitem override="none"><programlisting format="linespecific" language="java" linenumbering="numbered" startinglinenumber="1"><![CDATA[ ]]><token><![CDATA[for]]></token><![CDATA[ (]]><token><![CDATA[int]]></token><![CDATA[ ]]><methodname><![CDATA[i]]></methodname><![CDATA[ = 0; ]]><methodname><![CDATA[i]]></methodname><![CDATA[ < 5; ]]><methodname><![CDATA[i]]></methodname><![CDATA[++)]]>
<![CDATA[ {]]>
<![CDATA[   ]]><lineannotation><![CDATA[// i はこのブロック内でしか使えない]]></lineannotation>
<lineannotation></lineannotation><![CDATA[   ...]]>
<![CDATA[ }]]>
</programlisting></listitem></itemizedlist></section></section></article>