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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_877</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_876.html">< previous page</a></td> <td align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_877</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_878.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 877</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">Increment()</font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table><table cellspacing="0" border="0" width="336" cellpadding="4"><tr><td valign="top"><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">Increment聽day聽by聽1<br />IF聽day聽>聽number聽of聽days聽in聽month聽mo<br />聽聽聽Set聽day聽=聽1<br />聽聽聽Increment聽mo聽by聽1<br />聽聽聽IF聽mo聽>聽12<br />聽聽聽聽聽聽Set聽mo聽=聽1<br />聽聽聽聽聽聽Increment聽yr聽by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><br /><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 can code the algorithm for finding the number of days in a month as a separate functionan auxiliary (helper) function that is not a member of the </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">DateType</font><font face="Times New Roman, Times, Serif" size="3"> class. In this function, we set up a local 12-element </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">int</font><font face="Times New Roman, Times, Serif" size="3"> array, </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">numDays</font><font face="Times New Roman, Times, Serif" size="3">, containing the number of days in each month. That is, </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">numDays[0]</font><font face="Times New Roman, Times, Serif" size="3"> = 31, </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">numDays[1]</font><font face="Times New Roman, Times, Serif" size="3"> = 28, </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">numDays[2]</font><font face="Times New Roman, Times, Serif" size="3"> = 31, and so on, giving the number of days in January, February, March, . The number of days in February might need to be adjusted for leap year, so this function must receive as parameters both a month and a year.</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"><img src="3e26ecb1b6ac508ae10a0e39d2fb98b2.gif" border="0" width="29" height="1" alt="3e26ecb1b6ac508ae10a0e39d2fb98b2.gif" /></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">DaysInMonth聽(In:聽month,聽year)<br />Out:聽Function聽value</font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table><table cellspacing="0" border="0" width="643" cellpadding="4"><tr><td valign="top"><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">Declare聽a聽12-element聽integer聽array,聽numDays,聽and聽initialize聽numDays[0]聽to聽31,<br />聽聽numDays[1]聽to聽28,聽and聽so聽forth<br />IF聽month聽isn't聽2<br />聽聽Return聽numDays[month1]<br />//聽It's聽February.聽Check聽for聽leap聽year<br />IF聽(year聽MOD聽4聽is聽0聽AND聽year聽MOD聽100聽isn't聽0)聽OR聽year聽MOD聽400聽is聽0<br />聽聽Return聽29<br />ELSE<br />聽聽Return聽28</font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table></td></tr></table><br /><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">Testing: To test the </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">Increment</font><font face="Times New Roman, Times, Serif" size="3"> function, we need to create a driver that calls the function with different values for the date. Values that cause the month to change must be tested, as well as values that cause the year to change. Leap year must be tested, including a year with the last two digits 00. Case Study Follow-Up Exercise 3 asks you to carry out this testing.</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">Here is the implementation file that contains function definitions for all of the ADT operations:</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_876.html">< previous page</a></td> <td align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_877</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_878.html">next page ></a></td> </tr> </table> </body> </html>⌨️ 快捷键说明
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