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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>Hyperlinked ECMA C# Language Specification</title><meta name="author" content="Jon Jagger" /><link rel="stylesheet" href="ecma334.css"></link></head><body><div align="right"><em><a href="http://www.jaggersoft.com">Jon Jagger</a></em></div><div align="right"><a href="mailto:jon@jaggersoft.com">jon@jaggersoft.com</a></div><form method="get" action="http://search.atomz.com/search/"><input size="30" name="sp-q"></input><input type="submit" value="Search C# Spec"></input><input type="hidden" name="sp-a" value="sp10024177"></input><input type="hidden" name="sp-f" value="ISO-8859-1"></input></form><a href="toc.htm">Table of Contents</a> <a href="1.htm">1</a> <a href="2.htm">2</a> <a href="3.htm">3</a> <a href="4.htm">4</a> <a href="5.htm">5</a> <a href="6.htm">6</a> <a href="7.htm">7</a> <a href="8.htm">8</a> <a href="9.htm">9</a> <a href="10.htm">10</a> <a href="11.htm">11</a> <a href="12.htm">12</a> <a href="13.htm">13</a> <a href="14.htm">14</a> <a href="15.htm">15</a> <a href="16.htm">16</a> <a href="17.htm">17</a> <a href="18.htm">18</a> <a href="19.htm">19</a> <a href="20.htm">20</a> <a href="21.htm">21</a> <a href="22.htm">22</a> <a href="23.htm">23</a> <a href="24.htm">24</a> <a href="25.htm">25</a> <a href="notes.htm">Notes</a> <a href="HyperlinkedCSharpECMA.zip">Download</a><span class="ruler"></span><span class="heading">ECMA-334 C# Language Specification</span><span class="navigate"><a href="14.2.htm"><img src="previous.gif" alt="previous" border="0" /></a><a href="14.2.2.htm"><img src="next.gif" alt="next" border="0" /></a></span><span class="clause-depth"><a href="13.htm"><img src="previous.gif" alt="previous at this level" border="0" /></a><a href="15.htm"><img src="next.gif" alt="next at this level" border="0" /></a> <span class="clause-number-link"><a href="14.htm">14</a></span><span class="clause-title-previous"> Expressions</span></span><span class="clause-depth"><a href="14.1.htm"><img src="previous.gif" alt="previous at this level" border="0" /></a><a href="14.3.htm"><img src="next.gif" alt="next at this level" border="0" /></a> <span class="clause-number-link"><a href="14.2.htm">14.2</a></span><span class="clause-title-previous"> Operators</span></span><span class="clause-depth"><a href="14.2.1.htm"><img src="previous.gif" alt="previous at this level" border="0" /></a><a href="14.2.2.htm"><img src="next.gif" alt="next at this level" border="0" /></a> <span class="clause-number">14.2.1</span><span class="clause-title"> Operator precedence and associativity</span></span><span class="locator">
Paragraph 1</span><span class="paragraph"><span class="sentence"><span class="sentence-number">1</span> <a name="P1S1"></a>When an expression contains multiple operators, the precedence of the operators controls the order in which the individual operators are evaluated.</span> <span class="note">[Note: For example, the expression x + y * z is evaluated as x + (y * z) because the * operator has higher precedence than the binary + operator. end note]</span> <span class="sentence"><span class="sentence-number">2</span> <a name="P1S2"></a>The precedence of an operator is established by the definition of its associated grammar production.</span> <span class="note">[Note: For example, an <span class="non-terminal"><a href="14.7.htm#additive-expression">additive-expression</a></span> consists of a sequence of <span class="non-terminal"><a href="14.7.htm#multiplicative-expression">multiplicative-expression</a></span>s separated by + or -operators, thus giving the + and -operators lower precedence than the *, /, and % operators. end note]</span> </span><span class="locator">
Paragraph 2</span><span class="paragraph"><span class="sentence"><span class="sentence-number">1</span> <a name="P2S1"></a>The following table summarizes all operators in order of precedence from highest to lowest:
<table border="1">
<tr>
<th align="left">Section</th>
<th align="left">Category</th>
<th align="left">Operators</th>
</tr>
<tr>
<td><a href="14.5.htm">14.5</a></td>
<td>Primary</td>
<td><span class="fragment">x.y f(x) [x] x++ x-- new</br>typeof checked unchecked</span></td>
</tr>
<tr>
<td><a href="14.6.htm">14.6</a></td>
<td>Unary</td>
<td><span class="fragment">+ - ! ~ ++x --x (T)x</span></td>
</tr>
<tr>
<td><a href="14.7.htm">14.7</a></td>
<td>Multiplicative</td>
<td><span class="fragment">* / %</span></td>
</tr>
<tr>
<td><a href="14.7.htm">14.7</a></td>
<td>Additive</td>
<td><span class="fragment">+ -</span></td>
</tr>
<tr>
<td><a href="14.8.htm">14.8</a></td>
<td>Shift</td>
<td><span class="fragment"><< >></span></td>
</tr>
<tr>
<td><a href="14.9.htm">14.9</a></td>
<td>Relational and</br>type-testing</td>
<td><span class="fragment">< > <= >= is as</span></td>
</tr>
<tr>
<td><a href="14.9.htm">14.9</a></td>
<td>Equality</td>
<td><span class="fragment">== !=</span></td>
</tr>
<tr>
<td><a href="14.10.htm">14.10</a></td>
<td>Logical AND</td>
<td><span class="fragment">&</span></td>
</tr>
<tr>
<td><a href="14.10.htm">14.10</a></td>
<td>Logical XOR</td>
<td><span class="fragment">^</span></td>
</tr>
<tr>
<td><a href="14.10.htm">14.10</a></td>
<td>Logical OR</td>
<td><span class="fragment">|</span></td>
</tr>
<tr>
<td><a href="14.11.htm">14.11</a></td>
<td>Conditional AND</td>
<td><span class="fragment">&&</span></td>
</tr>
<tr>
<td><a href="14.11.htm">14.11</a></td>
<td>Conditional OR</td>
<td><span class="fragment">||</span></td>
</tr>
<tr>
<td><a href="14.12.htm">14.12</a></td>
<td>Conditional</td>
<td><span class="fragment">?:</span></td>
</tr>
<tr>
<td><a href="14.13.htm">14.13</a></td>
<td>Assignment</td>
<td><span class="fragment">= *= /= %= +-= -= <<= >>= &= ^= |=</span></td>
</tr>
</table>
When an operand occurs between two operators with the same precedence, the associativity of the operators controls the order in which the operations are performed: </span><ul><li><span class="sentence"><span class="sentence-number">2</span> <a name="P2S2"></a> Except for the assignment operators, all binary operators are left-associative, meaning that operations are performed from left to right.</span> <span class="example">[Example: For example, x + y + z is evaluated as (x + y) + z. end example]</span> </li><li><span class="sentence"><span class="sentence-number">3</span> <a name="P2S3"></a> The assignment operators and the conditional operator (?:) are right-associative, meaning that operations are performed from right to left.</span> <span class="example">[Example: For example, x = y = z is evaluated as x = (y = z). end example]</span> </li></ul></span><span class="locator">
Paragraph 3</span><span class="paragraph"><span class="sentence"><span class="sentence-number">1</span> <a name="P3S1"></a>Precedence and associativity can be controlled using parentheses.</span> <span class="example">[Example: For example, x + y * z first multiplies y by z and then adds the result to x, but (x + y) * z first adds x and y and then multiplies the result by z. end example]</span> </span><span class="ruler"></span><table><tr><td><table align="left" bgcolor="navy"><tr bgcolor="navy"><td><font face="Arial,sans-serif" size="6" color="yellow"><strong>{ JSL }</strong></font></td></tr></table></td></tr><tr><td><font face="Arial,sans-serif" size="2" color="navy"><strong>Jagger Software Ltd</strong></font></td></tr><tr><td><font face="Arial,sans-serif" size="2" color="navy"><strong>Company # 4070126</strong></font></td></tr><tr><td><font face="Arial,sans-serif" size="2" color="navy"><strong>VAT # 762 5213 42</strong></font></td></tr></table><img src="valid-html401.png" align="left" height="31" width="88" alt="Valid HTML 4.01" /><img src="vcss.gif" align="left" height="31" width="88" alt="Valid CSS" /></body></html>⌨️ 快捷键说明
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