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📁 This ECMA Standard specifies the form and establishes the interpretation of programs written in the
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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="17.4.4.htm"><img src="previous.gif" alt="previous" border="0" /></a><a href="17.4.5.1.htm"><img src="next.gif" alt="next" border="0" /></a></span><span class="clause-depth"><a href="16.htm"><img src="previous.gif" alt="previous at this level" border="0" /></a><a href="18.htm"><img src="next.gif" alt="next at this level" border="0" /></a> <span class="clause-number-link"><a href="17.htm">17</a></span><span class="clause-title-previous"> Classes</span></span><span class="clause-depth"><a href="17.3.htm"><img src="previous.gif" alt="previous at this level" border="0" /></a><a href="17.5.htm"><img src="next.gif" alt="next at this level" border="0" /></a> <span class="clause-number-link"><a href="17.4.htm">17.4</a></span><span class="clause-title-previous"> Fields</span></span><span class="clause-depth"><a href="17.4.4.htm"><img src="previous.gif" alt="previous at this level" border="0" /></a><a href="17.4.5.htm"><img src="next.gif" alt="next at this level" border="0" /></a> <span class="clause-number">17.4.5</span><span class="clause-title"> Variable initializers</span></span><span class="locator">
     Paragraph 1</span><span class="paragraph"><span class="sentence"><span class="sentence-number">1</span> <a name="P1S1"></a>Field declarations may include <span class="non-terminal"><a href="19.6.htm#variable-initializer">variable-initializer</a></span>s.</span> <span class="sentence"><span class="sentence-number">2</span> <a name="P1S2"></a>For static fields, variable initializers correspond to assignment statements that are executed during class initialization.</span> <span class="sentence"><span class="sentence-number">3</span> <a name="P1S3"></a>For instance fields, variable initializers correspond to assignment statements that are executed when an instance of the class is created.</span> </span><span class="paragraph"><span class="example">[Example: The example <pre class="code-example">
using System;  
class Test  
{  
   static double x = Math.Sqrt(2.0);  
   int i = 100;  
   string s = "Hello";  
   static void Main() {  
      Test a = new Test();  
      Console.WriteLine("x = {0}, i = {1}, s = {2}", x, a.i, a.s);  
   }  
}  
</pre>produces the output <pre class="code-example">
x = 1.4142135623731, i = 100, s = Hello  
</pre>because an assignment to x occurs when static field initializers execute and assignments to i and s occur when the instance field initializers execute. end example]</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 default value initialization described in <a href="17.4.3.htm">&#167;17.4.3</a> occurs for all fields, including fields that have variable initializers.</span> <span class="sentence"><span class="sentence-number">2</span> <a name="P2S2"></a>Thus, when a class is initialized, all static fields in that class are first initialized to their default values, and then the static field initializers are executed in textual order.</span> <span class="sentence"><span class="sentence-number">3</span> <a name="P2S3"></a>Likewise, when an instance of a class is created, all instance fields in that instance are first initialized to their default values, and then the instance field initializers are executed in textual order.</span> </span><span class="locator">
     Paragraph 3</span><span class="paragraph"><span class="sentence"><span class="sentence-number">1</span> <a name="P3S1"></a>It is possible for static fields with variable initializers to be observed in their default value state.</span> <span class="example">[Example: However, this is strongly discouraged as a matter of style. The example <pre class="code-example">
using System;  
class Test  
{  
   static int a = b + 1;  
   static int b = a + 1;  
   static void Main() {  
      Console.WriteLine("a = {0}, b = {1}", a, b);  
   }  
}  
</pre>exhibits this behavior. Despite the circular definitions of a and b, the program is valid. It results in the output <pre class="code-example">
a = 1, b = 2  
</pre>because the static fields a and b are initialized to 0 (the default value for <span class="keyword">int</span>) before their initializers are executed. When the initializer for a runs, the value of b is zero, and so a is initialized to 1. When the initializer for b runs, the value of a is already 1, and so b is initialized to 2. 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>
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