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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_358</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_357.html">< previous page</a></td> <td align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_358</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_359.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 358</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">void聽Calc(聽聽/*聽in聽*/聽聽聽聽int聽聽alpha,<br />聽聽聽聽聽聽聽聽聽聽聽聽/*聽inout聽*/聽聽&聽beta聽聽聽)<br />//聽Precondition:<br />//聽聽聽聽alpha聽and聽beta聽are聽assigned<br />//聽Postcondition<br />//聽聽聽聽beta聽==聽beta@entry聽*聽7聽-聽alpha<br /><br />{<br />聽聽聽聽beta聽=聽beta聽*聽7聽-聽alpha;<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">This function first inspects the incoming value of </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">beta</font><font face="Times New Roman, Times, Serif" size="3"> so that it can evaluate the expression to the right of the equal sign. Then it stores a new value into </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">beta</font><font face="Times New Roman, Times, Serif" size="3"> by using the assignment operation. The data flow for </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">beta</font><font face="Times New Roman, Times, Serif" size="3"> is therefore considered a two-way flow of information. Pass-by-value is appropriate for </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">alpha</font><font face="Times New Roman, Times, Serif" size="3"> (it's incoming only), but pass-by-reference is required for </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">beta</font><font face="Times New Roman, Times, Serif" size="3"> (it's an incoming/outgoing parameter).</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="662" 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="Times New Roman, Times, Serif" size="3"><i>M</i></font><i><font face="Times New Roman, Times, Serif" size="1">ATTERS OF STYLE</font></i></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table></td></tr><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="Times New Roman, Times, Serif" size="3">Formatting Function Headings</font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table></td></tr><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="Times New Roman, Times, Serif" size="3">From here on, we follow a specific style when coding our function headings. Comments appear next to the formal parameters to explain how each parameter is used. Also, embedded comments indicate which of the three data flow categories each parameter belongs to (</font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">in</font><font face="Times New Roman, Times, Serif" size="3">, </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">out</font><font face="Times New Roman, Times, Serif" size="3">, or </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">inout</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></td></tr><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">void聽Print(聽聽/*聽in聽*/聽聽聽聽聽float聽val,聽聽聽聽聽聽聽聽//聽Value聽to聽be聽printed<br />聽聽聽聽聽聽聽聽聽聽聽聽聽/*聽inout聽*/聽int&聽count聽)聽聽聽聽聽聽聽//聽Number聽of聽lines聽printed<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聽聽聽聽聽聽聽聽//聽聽聽聽聽so聽far</font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table></td></tr><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="Times New Roman, Times, Serif" size="3">Notice that the first parameter is a value parameter. The second is a reference parameter, presumably because the function changes the value of the counter.</font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table></td></tr><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="Times New Roman, Times, Serif" size="3">We use comments in the form of rows of asterisks (or dashes or some other character) before and after a function to make the function stand out from the surrounding code. Each function also has its own block of introductory comments, just like those at the start of a program, as well as its precondition and postcondition.</font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table></td></tr><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="Times New Roman, Times, Serif" size="3">It's important to put as much care into documenting each function as you would into the documentation at the beginning of a program.</font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table></td></tr></table><br /></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_357.html">< previous page</a></td> <td align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_358</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_359.html">next page ></a></td> </tr> </table> </body> </html>⌨️ 快捷键说明
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