Java基础知识——变量类型

超、凢脫俗 2021-12-12 05:13 265阅读 0赞

Java基本数据类型

数值型：byte、short、int、long、float、double
    字符型：char
    布尔型：boolean
    引用数据类型：class、interface、数组

<table> 
 <thead> 
  <tr> 
   <th>数据类型</th> 
   <th>字节数</th> 
   <th>表数范围</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>byte</td> 
   <td>1</td> 
   <td>（-128~127)</td> 
  </tr> 
  <tr> 
   <td>short</td> 
   <td>2</td> 
   <td>-2^15~ 2^15-1（-32768~32767）</td> 
  </tr> 
  <tr> 
   <td>int</td> 
   <td>4</td> 
   <td>-2^31~ 2^31-1</td> 
  </tr> 
  <tr> 
   <td>long</td> 
   <td>8</td> 
   <td>-2^63~ 2^63-1</td> 
  </tr> 
  <tr> 
   <td>float</td> 
   <td>4</td> 
   <td>-3.403E38~3.403E38</td> 
  </tr> 
  <tr> 
   <td>double</td> 
   <td>8</td> 
   <td>-1.798E308~1.798E308</td> 
  </tr> 
  <tr> 
   <td>char</td> 
   <td>2</td> 
   <td>\u0000~\uFFFF</td> 
  </tr> 
  <tr> 
   <td>boolean</td> 
   <td>1位</td> 
   <td>true或 false</td> 
  </tr> 
  <tr> 
   <td>class</td> 
   <td>4</td> 
   <td></td> 
  </tr> 
  <tr> 
   <td>interface</td> 
   <td>4</td> 
   <td></td> 
  </tr> 
  <tr> 
   <td>a[ ]</td> 
   <td>4</td> 
   <td></td> 
  </tr> 
 </tbody> 
</table>

float类型赋值时需要加后缀F/f
    long类型赋值时需要加后缀L/l

<table> 
 <thead> 
  <tr> 
   <th>转义符</th> 
   <th>含义</th> 
   <th>Unicode值</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>\b</td> 
   <td>退格</td> 
   <td>\u0000</td> 
  </tr> 
  <tr> 
   <td>\n</td> 
   <td>换行</td> 
   <td>\u000a</td> 
  </tr> 
  <tr> 
   <td>\r</td> 
   <td>回车</td> 
   <td>\u000b</td> 
  </tr> 
  <tr> 
   <td>\t</td> 
   <td>制表符</td> 
   <td>\u0009</td> 
  </tr> 
  <tr> 
   <td>"</td> 
   <td>双引号</td> 
   <td>\u0022</td> 
  </tr> 
  <tr> 
   <td>’</td> 
   <td>单引号</td> 
   <td>\u0027</td> 
  </tr> 
  <tr> 
   <td>\</td> 
   <td>反斜杠</td> 
   <td>\u005c</td> 
  </tr> 
 </tbody> 
</table>