📄 8.7.6.htm
字号:
<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="8.7.5.htm"><img src="previous.gif" alt="previous" border="0" /></a><a href="8.7.7.htm"><img src="next.gif" alt="next" border="0" /></a></span><span class="clause-depth"><a href="7.htm"><img src="previous.gif" alt="previous at this level" border="0" /></a><a href="9.htm"><img src="next.gif" alt="next at this level" border="0" /></a> <span class="clause-number-link"><a href="8.htm">8</a></span><span class="clause-title-previous"> Language Overview</span></span><span class="clause-depth"><a href="8.6.htm"><img src="previous.gif" alt="previous at this level" border="0" /></a><a href="8.8.htm"><img src="next.gif" alt="next at this level" border="0" /></a> <span class="clause-number-link"><a href="8.7.htm">8.7</a></span><span class="clause-title-previous"> Classes</span></span><span class="clause-depth"><a href="8.7.5.htm"><img src="previous.gif" alt="previous at this level" border="0" /></a><a href="8.7.7.htm"><img src="next.gif" alt="next at this level" border="0" /></a> <span class="clause-number">8.7.6</span><span class="clause-title"> Operators</span></span><span class="informative"><span class="paragraph">An operator is a member that defines the meaning of an expression operator that can be applied to instances of the class. There are three kinds of operators that can be defined: unary operators, binary operators, and conversion operators. </span><span class="paragraph">The following example defines a Digit type that represents <span class="keyword">decimal</span> digits-integral values between 0 and 9. <pre class="code-example">
using System;
public struct Digit
{
byte value;
public Digit(byte value) {
if (value < 0 || value > 9) throw new ArgumentException();
this.value = value;
}
public Digit(int value): this((byte) value) {}
public static implicit operator byte(Digit d) {
return d.value;
}
public static explicit operator Digit(byte b) {
return new Digit(b);
}
public static Digit operator+(Digit a, Digit b) {
return new Digit(a.value + b.value);
}
public static Digit operator-(Digit a, Digit b) {
return new Digit(a.value - b.value);
}
public static bool operator==(Digit a, Digit b) {
return a.value == b.value;
}
public static bool operator!=(Digit a, Digit b) {
return a.value != b.value;
}
public override bool Equals(object value) {
if (value == null) return false;
if (GetType() == value.GetType()) return this == (Digit)value;
return false; }
public override int GetHashCode() {
return value.GetHashCode();
}
public override string ToString() {
return value.ToString();
}
}
class Test
{
static void Main() {
Digit a = (Digit) 5;
Digit b = (Digit) 3;
Digit plus = a + b;
Digit minus = a - b;
bool equals = (a == b);
Console.WriteLine("{0} + {1} = {2}", a, b, plus);
Console.WriteLine("{0} - {1} = {2}", a, b, minus);
Console.WriteLine("{0} == {1} = {2}", a, b, equals);
}
}
</pre></span><span class="paragraph">The Digit type defines the following operators: <ul><li> An implicit conversion operator from Digit to <span class="keyword">byte</span>. </li><li> An explicit conversion operator from <span class="keyword">byte</span> to Digit. </li><li> An addition operator that adds two Digit values and returns a Digit value. </li><li> A subtraction operator that subtracts one Digit value from another, and returns a Digit value. </li><li> The equality (==) and inequality (!=) operators, which compare two Digit values. </li></ul></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
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -