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<html><head><title>JAVA编程语言</title><meta http-equiv="Content-Type" content="text/html; charset=gb2312"><link rel="stylesheet" href="../../../css/text.css" type="text/css"><script language="JavaScript" type="text/JavaScript"><!--function MM_openBrWindow(theURL,winName,features) { //v2.0 window.open(theURL,winName,features);}//--></script></head><body bgcolor="#FFFFFF" text="#000000" leftmargin="0" topmargin="0" marginwidth="0" marginheight="0" ><table width="100%" border="0" cellpadding="0" cellspacing="0" bgcolor="#FFFFFF"> <tr> <td valign="top"> <table width="95%" border="0" cellspacing="0" cellpadding="0" align="center" bgcolor="#FFFFFF"> <tr> <td valign="top"> <p> <span class="pt9-black"> 表达式是由操作数和运算符按一定的语法形式组成的符号序列。一个常量或一个变量名字是最简单的表达式，其值即该常量或变量的值；表达式的值还可以用作其他运算的操作数，形成更复杂的表达式。<br> <br> </span><span class="zhongdian">1．表达式的类型<a name="01"></a></span><span class="pt9-black"><br> <br> 表达式的类型由运算以及参与运算的操作数的类型决定，可以是简单类型，也可以是复合类型：<br> <b>布尔型表达式</b>： x&&y||z;<br> <b>整型表达式</b>： num1+num2;</span><br> <br> <span class="zhongdian">2．运算符的优先次序<a name="02"></a></span><span class="pt9-black"><br> <br> 表达式的运算按照运算符的优先顺序从高到低进行,同级运算符从左到右进行：<br> </span></p> <table width="70%" border="0" cellspacing="1" cellpadding="0" align="center" bgcolor="#006633"> <tr bgcolor="#FFFFFF"> <td class="pt9-black" width="30%"> <div align="center"><b>优先次序</b></div> </td> <td class="pt9-black"> <div align="center"><b>运算符</b></div> </td> </tr> <tr bgcolor="#FFFFFF"> <td class="pt9-black" width="30%"> <div align="center">1</div> </td> <td class="pt9-black"> <div align="center">. [] () </div> </td> </tr> <tr bgcolor="#FFFFFF"> <td class="pt9-black" width="30%"> <div align="center">2</div> </td> <td class="pt9-black"> <div align="center">++ -- ! ~ instanceof</div> </td> </tr> <tr bgcolor="#FFFFFF"> <td class="pt9-black" width="30%"> <div align="center">3</div> </td> <td class="pt9-black"> <div align="center">new (type)</div> </td> </tr> <tr bgcolor="#FFFFFF"> <td class="pt9-black" width="30%"> <div align="center">4</div> </td> <td class="pt9-black"> <div align="center">* / % </div> </td> </tr> <tr bgcolor="#FFFFFF"> <td class="pt9-black" width="30%"> <div align="center">5</div> </td> <td class="pt9-black"> <div align="center">+ - </div> </td> </tr> <tr bgcolor="#FFFFFF"> <td class="pt9-black" width="30%"> <div align="center">6</div> </td> <td class="pt9-black"> <div align="center">>> >>> <<</div> </td> </tr> <tr bgcolor="#FFFFFF"> <td class="pt9-black" width="30%"> <div align="center">7</div> </td> <td class="pt9-black"> <div align="center">> < >= <= </div> </td> </tr> <tr bgcolor="#FFFFFF"> <td class="pt9-black" width="30%"> <div align="center">8</div> </td> <td class="pt9-black"> <div align="center">= = != </div> </td> </tr> <tr bgcolor="#FFFFFF"> <td class="pt9-black" width="30%"> <div align="center">9</div> </td> <td class="pt9-black"> <div align="center">&</div> </td> </tr> <tr bgcolor="#FFFFFF"> <td class="pt9-black" width="30%"> <div align="center">10</div> </td> <td class="pt9-black"> <div align="center">^</div> </td> </tr> <tr bgcolor="#FFFFFF"> <td class="pt9-black" width="30%"> <div align="center">11</div> </td> <td class="pt9-black"> <div align="center">| </div> </td> </tr> <tr bgcolor="#FFFFFF"> <td class="pt9-black" width="30%"> <div align="center">12</div> </td> <td class="pt9-black"> <div align="center">&&</div> </td> </tr> <tr bgcolor="#FFFFFF"> <td class="pt9-black" width="30%"> <div align="center">13</div> </td> <td class="pt9-black"> <div align="center">||</div> </td> </tr> <tr bgcolor="#FFFFFF"> <td class="pt9-black" width="30%"> <div align="center">14</div> </td> <td class="pt9-black"> <div align="center">?:</div> </td> </tr> <tr bgcolor="#FFFFFF"> <td class="pt9-black" width="30%"> <div align="center">15</div> </td> <td class="pt9-black"> <div align="center">= += -= *= /= %= ^=</div> </td> </tr> <tr bgcolor="#FFFFFF"> <td class="pt9-black" width="30%"> <div align="center">16</div> </td> <td class="pt9-black"> <div align="center">&= |= <<= >>= >>>= </div> </td> </tr> </table> <br> <span class="pt9-black">例如，下述条件语句分四步完成：<br> Result=sum==0?1:num/sum;<br> 第1步：result=sum==0?1:(num/sum)<br> 第2步：result=(sum==0)?1:(num/sum)<br> 第3步：result=((sum==0)?1:(num/sum))<br> 第4步：result=<br> <br> <a href="#" onClick="MM_openBrWindow('222f.htm','','width=360,height=180')">--观看动画--</a> <br> </span> <p><span class="pt9-black"><br> </span> </p> </td> </tr> </table> </td> </tr></table></body></html>⌨️ 快捷键说明
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