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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <title>page_604</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_603.html">< previous page</a></td> <td align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_604</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_605.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 604</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">Passing an array as a parameter gives the function access to the entire array. Later in the chapter, we look at parameter passage in detail.</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"><i>Examples of Declaring and Accessing Arrays</i></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">We now look in detail at some specific examples of declaring and accessing arrays. Here are some declarations that a program might use to analyze occupancy rates in an apartment building:</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">const聽int聽BUILDING_SIZE聽=聽350;聽聽聽//聽Number聽of聽apartments<br /><br />int聽occupants[BUILDING_SIZE];聽聽聽聽//聽occupants[i]聽is聽the聽number聽of<br />聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽//聽聽聽occupants聽in聽apartment聽i<br />int聽totalOccupants;聽聽聽聽聽聽聽聽聽聽聽聽聽聽//聽Total聽number聽of聽occupants<br />int聽counter;聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽//聽Loop聽control聽and聽index聽variable</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="3">occupants</font><font face="Times New Roman, Times, Serif" size="3"> is a 350-element array of type </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">int</font><font face="Times New Roman, Times, Serif" size="3"> (see Figure 11-6). </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">occupants[0]</font><font face="Times New Roman, Times, Serif" size="3"> =3 if the first apartment has three occupants; </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">occupants[1]</font><font face="Times New Roman, Times, Serif" size="3"> =5 if the second apartment has five occupants; and so on. If values have been stored into the array, then the following code totals the number of occupants in the building.</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">totalOccupants聽=聽0;<br />for聽(counter聽=聽0;聽counter聽<聽BUILDING_SIZE;聽counter++)<br /><br />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totalOccupants聽==聽sum聽of聽occupants[0..counter-1]<br />聽聽聽聽聽聽聽聽//聽聽&&聽0聽<=聽counter聽<=聽BUILDING_SIZE<br /><br />聽聽聽聽totalOccupants聽=聽totalOccupants聽+聽occupants[counter];</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">The first time through the loop, </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">counter</font><font face="Times New Roman, Times, Serif" size="3"> is 0. We add the contents of </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">totalOccupants</font><font face="Times New Roman, Times, Serif" size="3"> (which is 0) to the contents of </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">occupants[0]</font><font face="Times New Roman, Times, Serif" size="3">, storing the</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="3"><img src="fa46795a9236bf045fbb9e1fccf003e1.gif" border="0" alt="0604-01.gif" width="173" height="172" /></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 11-6<br />occupants Array</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_603.html">< previous page</a></td> <td align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_604</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_605.html">next page ></a></td> </tr> </table> </body> </html>⌨️ 快捷键说明
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