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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_718</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_717.html">< previous page</a></td> <td align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_718</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_719.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 718</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">we can use the following declaration.</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">int聽table[2][3]聽=<br />{<br />聽聽聽聽{14,聽3,聽-5},<br />聽聽聽聽{0,聽46,聽7}<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">In this declaration, the initializer list consists of two items, each of which is itself an initializer list. The first inner initializer list stores 14, 3, and -5 into row 0 of the table; the second stores 0, 46, and 7 into row 1. The use of two initializer lists makes sense if you think of each row of the table as a onedimensional array of three </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">ints</font><font face="Times New Roman, Times, Serif" size="3">. The first initializer list initializes the first array (the first row), and the second list initializes the second array (the second row). Later in the chapter, we revisit this notion of viewing a twodimensional array as an array of arrays.</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">Initializing a table in its declaration is impractical if the table is large. For a 100-row by 100-column table, you don't want to list 10,000 values. If the values are all different, you should store them into a file and input them into the table at run time. If the values are all the same, the usual approach is to use nested For loops and an assignment statement. Here is a generalpurpose code segment that zeroes out a table with </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">NUM_ROWS</font><font face="Times New Roman, Times, Serif" size="3"> rows and </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">NUM_COLS</font><font face="Times New Roman, Times, Serif" size="3"> columns:</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">for聽(row聽=聽0;聽row聽<聽NUM_ROWS;聽row++)<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table[0..row-1][0..NUM_COLS-1]聽==聽0<br />聽聽聽聽聽聽聽聽//聽聽&&聽0聽<=聽row聽<=聽NUM_ROWS<br /><br />聽聽聽聽for聽(col聽=聽0;聽col聽<聽NUM_COLS;聽col++)<br /><br />聽聽聽聽聽聽聽聽聽聽聽聽//聽Invariant聽(prior聽to聽test):<br />聽聽聽聽聽聽聽聽聽聽聽聽//聽聽聽聽聽table[row][0..col1]聽==聽0<br />聽聽聽聽聽聽聽聽聽聽聽聽//聽聽&&聽0聽<=聽col聽<=聽NUM_COLS<br /><br />聽聽聽聽聽聽聽聽table[row][col]聽=聽0;</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">In this case, we initialized the table a row at a time, but we could just as easily have run through each column instead. The order doesn't matter as long as we access every element.</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>Print the Table</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">If we wish to print out a table with one row per line, then we have another case of row processing:</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_717.html">< previous page</a></td> <td align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_718</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_719.html">next page ></a></td> </tr> </table> </body> </html>⌨️ 快捷键说明
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