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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_781</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_780.html">< previous page</a></td> <td align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_781</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_782.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 781</font></td></tr></table><table border="0" cellspacing="0" cellpadding="0"><tr><td rowspan="5"></td> <td colspan="3" height="17"></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">Arrays of Records</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">Although single records can be useful, many applications require a collection of records. For example, a business needs a list of parts records, and a teacher needs a list of students in a class. Arrays are ideal for these applications. We simply define an array whose components are records.</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">Let's define a grade book to be a list of students as follows:</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MAX_STUDENTS聽=聽150;<br /><br />enum聽GradeType聽{A,聽B,聽C,聽D,聽F};<br /><br />typedef聽char聽NameString[16];<br /><br />struct聽StudentRec<br />{<br />聽聽聽聽NameString聽firstName;<br />聽聽聽聽NameString聽lastName;<br />聽聽聽聽float聽聽聽聽聽聽gpa;<br />聽聽聽聽int聽聽聽聽聽聽聽聽programGrade;<br />聽聽聽聽int聽聽聽聽聽聽聽聽quizGrade;<br />聽聽聽聽int聽聽聽聽聽聽聽聽finalExam;<br />聽聽聽聽GradeType聽聽courseGrade;<br />};<br /><br />StudentRec聽gradeBook[MAX_STUDENTS];<br />int聽聽聽聽聽聽聽聽length;<br />int聽聽聽聽聽聽聽聽count;</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 data structure can be visualized as shown in Figure 14-3.</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">An element of </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">gradeBook</font><font face="Times New Roman, Times, Serif" size="3"> is selected by an index. For example, </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">gradeBook[2]</font><font face="Times New Roman, Times, Serif" size="3"> is the third component in the array variable </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">gradeBook</font><font face="Times New Roman, Times, Serif" size="3">. Each component of </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">gradeBook</font><font face="Times New Roman, Times, Serif" size="3"> is a record of type </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">StudentRec</font><font face="Times New Roman, Times, Serif" size="3">. To access the course grade of the third student, we use the following expression:</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"><img src="9cd534716b48288031598e48f5472084.gif" border="0" alt="0781-01.gif" width="234" height="101" /></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">To access the first character in the last name of the third student, we use the following expression:</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_780.html">< previous page</a></td> <td align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_781</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_782.html">next page ></a></td> </tr> </table> </body> </html>⌨️ 快捷键说明
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