📄 page_663.html
字号:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <title>page_663</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_662.html">< previous page</a></td> <td align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_663</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_664.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 663</font></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">We need to keep track of the first possible place to look (</font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">first</font><font face="Times New Roman, Times, Serif" size="3">) and the last possible place to look (</font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">last</font><font face="Times New Roman, Times, Serif" size="3">). At any one time, we are looking only in </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">list[first]</font><font face="Times New Roman, Times, Serif" size="3"> through </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">list[last]</font><font face="Times New Roman, Times, Serif" size="3">. When the function begins, </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">first</font><font face="Times New Roman, Times, Serif" size="3"> is set to 0 and </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">last</font><font face="Times New Roman, Times, Serif" size="3"> is set to </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">length-1</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="Times New Roman, Times, Serif" size="3">This function needs the same five parameters as the previous search functions: the array containing the list, the item, the length of the list, a Boolean flag that tells whether the item was found, and the position of the item in the list (if it is there).</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">void聽BinSearch(<br />聽聽聽聽聽/*聽in聽*/聽const聽ItemType聽list[],聽聽聽聽//聽List聽to聽be聽searched<br />聽聽聽聽聽/*聽in聽*/聽聽聽聽聽聽聽ItemType聽item,聽聽聽聽聽聽//聽Item聽to聽be聽found<br />聽聽聽聽聽/*聽in聽*/聽聽聽聽聽聽聽int聽聽聽聽聽聽length,聽聽聽聽//聽Length聽of聽list<br />聽聽聽聽聽/*聽out聽*/聽聽聽聽聽聽int&聽聽聽聽聽index,聽聽聽聽聽//聽Location聽of聽item聽if聽found<br />聽聽聽聽聽/*聽out聽*/聽聽聽聽聽聽Boolean&聽found聽聽)聽聽聽//聽True聽if聽item聽is聽found<br /><br />//聽Searches聽list聽for聽item,聽returning聽the聽index<br />//聽of聽item聽if聽item聽was聽found<br /><br />//聽Precondition:<br />//聽聽聽聽聽length聽<=聽INT_MAX聽/聽2<br />//聽聽&&聽list[0..length-1]聽are聽in聽ascending聽order<br />//聽聽&&聽item聽is聽assigned<br />//聽Postcondition:<br />//聽聽聽聽聽IF聽item聽is聽in聽list<br />//聽聽聽聽聽聽聽聽聽found聽==聽TRUE聽聽&&聽聽list[index]聽==聽item<br />//聽聽聽聽聽ELSE<br />//聽聽聽聽聽聽聽聽聽found聽==聽FALSE聽聽&&聽聽index聽is聽undefined<br /><br />{<br />聽聽聽聽int聽first聽=聽0;聽聽聽聽聽聽聽聽聽聽聽聽聽//聽Lower聽bound聽on聽list<br />聽聽聽聽int聽last聽=聽length聽-聽1;聽聽聽聽聽//聽Upper聽bound聽on聽list<br />聽聽聽聽int聽middle;聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽//聽Middle聽index<br /><br />聽聽聽聽found聽=聽FALSE;<br />聽聽聽聽while聽(last聽>=聽first聽&&聽!found)<br />聽聽聽聽{<br />聽聽聽聽聽聽聽聽聽聽聽聽//聽Invariant聽(prior聽to聽test):<br />聽聽聽聽聽聽聽聽聽聽聽聽//聽聽聽聽聽If聽item聽is聽in聽list[0..length-1]聽then<br />聽聽聽聽聽聽聽聽聽聽聽聽//聽聽聽聽聽item聽is聽in聽list[first..last]<br /><br />聽聽聽聽聽聽聽聽middle聽=聽(first聽+聽last)聽/聽2;<br />聽聽聽聽聽聽聽聽if聽(item聽<聽list[middle])<br />聽聽聽聽聽聽聽聽聽聽聽聽//聽Assert:聽item聽is聽not聽in聽list[middle..last]<br />聽聽聽聽聽聽聽聽聽聽聽聽last聽=聽middle聽-聽1;<br />聽聽聽聽聽聽聽聽else聽if聽(item聽>聽list[middle])<br />聽聽聽聽聽聽聽聽聽聽聽聽聽//聽Assert:聽item聽is聽not聽in聽list[first..middle]<br />聽聽聽聽聽聽聽聽聽聽聽聽聽first聽=聽middle聽+聽1;</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_662.html">< previous page</a></td> <td align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_663</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_664.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 + -