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<div align="center" class="title">JAVA程序員必讀：基礎篇（3）語言基礎</div>
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<div align="center"><font color="#666666">編譯：ZSC/太平洋網絡學院</font></div>
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<div align="right" class="gray"><a href="mailto:tntst@pconline.com.cn">［責編:爆破手］</a></div>
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<p class="article"> <b>語言基礎</b> </p>
<p></p>
<p class="article"><b>3.1.1 數據類型</b></p>
<p class="article"> 每一個變量必須有一個數據類型。一個變量的數據類型決定了變量能容納的數值和操作符。比如 ，在MaxVariablesDemo程序中，聲明int
largestInteger決定了largestInteger是一個整型數據類型（int）。整型只能容納整型數（可以是正數也可以是負數）。你可以完成算術操作，比如，整型變量的加法等等。</p>
<p class="article"> JAVA程序語言有兩類的數據類型：原始和引用。一個原始類型的變量為它的類型包含了適當大小和格式的單一數值：一個數字、字符或者一個布爾型數值。比如，一個整型數值是一個32位數據。</p>
<p class="article"> 下面表格所有的JAVA支持的所有原始數據類型，還給出了它們的大小和格式以及簡短的描述。MaxVariablesDemo程序為每一個原始類型聲明了一個變量：</p>
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<p align="CENTER" class="article">關鍵字
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<p align="CENTER" class="article">描述
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<p align="CENTER" class="article">大小/格式
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<p align="CENTER" class="article">整型
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<p align="CENTER" class="article">byte
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<p align="CENTER" class="article">字節長度整型
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<p align="CENTER" class="article">8位兩個補碼
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<p align="CENTER" class="article">Short
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<p align="CENTER" class="article">短整型
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<td width="33%" valign="TOP">
<p align="CENTER" class="article">16位兩個補碼
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<td width="33%" valign="TOP">
<p align="CENTER" class="article">int
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<p align="CENTER" class="article">整型
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<td width="33%" valign="TOP">
<p align="CENTER" class="article">32位兩個補碼
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<td width="33%" valign="TOP">
<p align="CENTER" class="article">long
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<td width="33%" valign="TOP">
<p align="CENTER" class="article">長整型
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<td width="33%" valign="TOP">
<p align="CENTER" class="article">64位兩個補碼
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<p align="CENTER" class="article">實數
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<p align="CENTER" class="article">Float
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