📄 page_912.html
字号:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <title>page_912</title> <link rel="stylesheet" href="reset.css" type="text/css" media="all"> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> </head> <body> <table summary="top nav" border="0" width="100%"> <tr> <td align="left" width="30%" style="background: #EEF3E2"><a style="color: blue; font-size: 120%; font-weight: bold; text-decoration: none; font-family: verdana;" href="page_911.html">< previous page</a></td> <td align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_912</strong></td> <td align="right" width="30%" style="background: #EEF3E2"><a style="color: blue; font-size: 120%; font-weight: bold; text-decoration: none; font-family: verdana;" href="page_913.html">next page ></a></td> </tr> <tr> <td align="left" colspan="3" style="background: #ffffff; padding: 20px;"> <table border="0" width="100%" cellpadding="0"><tr><td align="center"> <table border="0" cellpadding="2" cellspacing="0" width="100%"><tr><td align="left"></td> <td align="right"></td> </tr></table></td></tr><tr><td align="left"><p></p><table border="0" cellspacing="0" cellpadding="0" width="100%"><tr><td align="right"><font face="Times New Roman, Times, Serif" size="2" color="#FF0000">Page 912</font></td></tr></table><table border="0" cellspacing="0" cellpadding="0" width="100%"><tr><td rowspan="5"></td> <td colspan="3" height="12"></td> <td rowspan="5"></td></tr><tr><td colspan="3"></td></tr><tr><td></td> <td align="center"><font face="Times New Roman, Times, Serif" size="3"><img src="b8c721b18cf476668929394154abbc0e.gif" border="0" alt="0912-01.gif" width="332" height="302" /></font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table><table border="0" cellspacing="0" cellpadding="0" width="100%"><tr><td rowspan="5"></td> <td colspan="3" height="12"></td> <td rowspan="5"></td></tr><tr><td colspan="3"></td></tr><tr><td></td> <td align="center"><font face="Times New Roman, Times, Serif" size="2">Figure聽16-4<br />Class聽Interface聽Diagram聽for聽</font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">Time</font><font face="Times New Roman, Times, Serif" size="2">聽Class</font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table><table border="0" cellspacing="0" cellpadding="0"><tr><td rowspan="5"></td> <td colspan="3" height="12"></td> <td rowspan="5"></td></tr><tr><td colspan="3"></td></tr><tr><td></td> <td><font face="Times New Roman, Times, Serif" size="3">off-the-shelf class on a system, the source code for the implementation is probably unavailable. Even if it is available, modifying it may introduce bugs into a previously debugged solution. Access to the source code also violates a principal benefit of abstraction: users of an abstraction should not need to know how it is implemented.</font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table><table border="0" cellspacing="0" cellpadding="0"><tr><td rowspan="5"></td> <td colspan="3" height="12"></td> <td rowspan="5"></td></tr><tr><td colspan="3"></td></tr><tr><td></td> <td><font face="Times New Roman, Times, Serif" size="3">In C++, as in other OOP languages, there is a far quicker and safer way in which to add time-zone features: use inheritance. Let's derive a new class from the </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">Time</font><font face="Times New Roman, Times, Serif" size="3"> class and then specialize it. This new, extended time classcall it </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">ExtTime</font><font face="Times New Roman, Times, Serif" size="3">inherits the members of its base class, </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">Time</font><font face="Times New Roman, Times, Serif" size="3">. Here is the declaration of </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">ExtTime</font><font face="Times New Roman, Times, Serif" size="3">:</font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table><table border="0" cellspacing="0" cellpadding="0"><tr><td rowspan="5"></td> <td colspan="3" height="12"></td> <td rowspan="5"></td></tr><tr><td colspan="3"></td></tr><tr><td></td> <td><font face="Courier New, Courier, Mono New, Courier, Mono" size="2">enum聽ZoneType聽{EST,聽CST,聽MST,聽PST,聽EDT,聽CDT,聽MDT,聽PDT};<br /><br />class聽ExtTime聽:聽public聽Time<br />{<br />public:<br />聽聽聽聽void聽Set(聽/*聽in聽*/聽int聽聽聽聽聽hours,<br />聽聽聽聽聽聽聽聽聽聽聽聽聽聽/*聽in聽*/聽int聽聽聽聽聽minutes,<br />聽聽聽聽聽聽聽聽聽聽聽聽聽聽/*聽in聽*/聽int聽聽聽聽聽seconds,<br />聽聽聽聽聽聽聽聽聽聽聽聽聽聽/*聽in聽*/聽ZoneType聽timeZone聽);<br />聽聽聽聽void聽Write()聽const;<br />聽聽聽聽ExtTime(聽聽/*聽in聽*/聽int聽聽聽聽聽聽initHrs,聽聽聽聽聽聽//聽Constructor<br />聽聽聽聽聽聽聽聽聽聽聽聽聽聽/*聽in聽*/聽int聽聽聽聽聽聽initMins,<br />聽聽聽聽聽聽聽聽聽聽聽聽聽聽/*聽in聽*/聽int聽聽聽聽聽聽initSecs,<br />聽聽聽聽聽聽聽聽聽聽聽聽聽聽/*聽in聽*/聽ZoneType聽initZone聽);<br /></font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table></td></tr></table><p><font size="0"></font></p>聽 </td> </tr> <tr> <td align="left" width="30%" style="background: #EEF3E2"><a style="color: blue; font-size: 120%; font-weight: bold; text-decoration: none; font-family: verdana;" href="page_911.html">< previous page</a></td> <td align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_912</strong></td> <td align="right" width="30%" style="background: #EEF3E2"><a style="color: blue; font-size: 120%; font-weight: bold; text-decoration: none; font-family: verdana;" href="page_913.html">next page ></a></td> </tr> </table> </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 + -