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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_491</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_490.html">< previous page</a></td> <td align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_491</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_492.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 491</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="Courier New, Courier, Mono New, Courier, Mono" size="2">聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽聽//聽Invariant:<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All聽previous聽values聽of聽amount聽were聽<<聽0.0<br /><br />聽聽聽聽}聽while聽(amount聽<<聽0.0);<br />}</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">Testing: We should test two separate aspects of the Rainfall program. First, we should verify that the program works correctly given valid input data. Supplying arbitrary rainfall amounts of zero or greater, we must confirm that the program correctly adds up the values and divides by 12 to produce the average. Also, we should make sure that the program behaves correctly whether we type y or n when prompted to continue.</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 second aspect to test is the data validation code that we included in the program. When entering a particular rainfall amount, we should type negative numbers repeatedly to verify that an error message is printed and that we are unable to escape the Do-While loop until we eventually type a nonnegative number. Similarly, when prompted to type y or n to process another recording site, we must press several incorrect keys to exercise the loop in the </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">GetYesOrNo</font><font face="Times New Roman, Times, Serif" size="3"> function. Here's a sample run showing the testing of the data validation code:</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">Enter聽rainfall聽amount聽1:<br />0<br />Enter聽rainfall聽amount聽2:<br />0<br />Enter聽rainfall聽amount聽3:<br />0<br />Enter聽rainfall聽amount聽4:<br />3.4<br />Enter聽rainfall聽amount聽5:<br />9.6<br />Enter聽rainfall聽amount聽6:<br />1.2<br />Enter聽rainfall聽amount聽7:<br />-3.4<br />Amount聽cannot聽be聽negative.聽Enter聽again:<br />-9<br />Amount聽cannot聽be聽negative.聽Enter聽again:<br />-4.2<br />Amount聽cannot聽be聽negative.聽Enter聽again:<br />1.3<br />Enter聽rainfall聽amount聽8:<br />0<br />Enter聽rainfall聽amount聽9:<br />0<br />Enter聽rainfall聽amount聽10:<br />0<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_490.html">< previous page</a></td> <td align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_491</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_492.html">next page ></a></td> </tr> </table> </body> </html>⌨️ 快捷键说明
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