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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_504</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_503.html">< previous page</a></td> <td align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_504</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_505.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 504</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">The only guarantee made by the C++ language is that</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">1聽=聽<i>sizeof</i></font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">char</font><font face="Courier New, Courier, Mono New, Courier, Mono" size="2">)聽<u><</u>聽<i>sizeof</i></font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">short</font><font face="Courier New, Courier, Mono New, Courier, Mono" size="2">)聽<u><</u>聽<i>sizeof</i></font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">int</font><font face="Courier New, Courier, Mono New, Courier, Mono" size="2">)聽<u><</u>聽<i>sizeof</i></font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">long</font><font face="Courier New, Courier, Mono New, Courier, Mono" size="2">)</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">and</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"><i>sizeof</i></font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">float</font><font face="Courier New, Courier, Mono New, Courier, Mono" size="2">)聽<u><</u>聽<i>sizeof</i></font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">double</font><font face="Courier New, Courier, Mono New, Courier, Mono" size="2">)聽<u><</u>聽<i>sizeof</i></font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">long聽double</font><font face="Courier New, Courier, Mono New, Courier, Mono" size="2">)</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">For聽numeric聽data,聽the聽size聽of聽a聽data聽object聽determines聽its聽range聽of聽values.聽Let's聽look聽in聽more聽detail聽at聽the聽sizes,聽ranges聽of聽values,聽and聽constants聽for聽each聽of聽the聽built-in聽types.</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" width="100%"><tr><td rowspan="5"><img src="3e26ecb1b6ac508ae10a0e39d2fb98b2.gif" border="0" width="96" height="1" alt="3e26ecb1b6ac508ae10a0e39d2fb98b2.gif" /></td> <td colspan="3" height="12"></td> <td rowspan="5"><img src="3e26ecb1b6ac508ae10a0e39d2fb98b2.gif" border="0" width="96" height="1" alt="3e26ecb1b6ac508ae10a0e39d2fb98b2.gif" /></td></tr><tr><td colspan="3" height="2"><table cellpadding="0" cellspacing="0" border="0"><tr><td></td></tr></table></td></tr><tr><td></td> <td><font face="Times New Roman, Times, Serif" size="2">Range of Values The interval within which values of a numeric type must fall, specified in terms of the largest and smallest allowable values.</font></td><td></td></tr><tr><td colspan="3" height="2"><table cellpadding="0" cellspacing="0" border="0"><tr><td></td></tr></table></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>Integral Types</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">Before looking at how the sizes of integral types affect their possible values, we remind you that the reserved word </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">unsigned</font><font face="Times New Roman, Times, Serif" size="3"> may precede the name of an integral type</font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">unsigned聽char</font><font face="Times New Roman, Times, Serif" size="3">, </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">unsigned聽short</font><font face="Times New Roman, Times, Serif" size="3">, </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">unsigned聽int</font><font face="Times New Roman, Times, Serif" size="3">, </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">unsigned聽long</font><font face="Times New Roman, Times, Serif" size="3">. Values of these types are nonnegative integers with values from 0 through some machine-dependent maximum value. Although we rarely use unsigned types in this book, we include them in this discussion for thoroughness.</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">Ranges of Values</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 following table displays sample ranges of values for the </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">char</font><font face="Times New Roman, Times, Serif" size="3">, </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">short</font><font face="Times New Roman, Times, Serif" size="3">, </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">int</font><font face="Times New Roman, Times, Serif" size="3">, and </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">long</font><font face="Times New Roman, Times, Serif" size="3"> data types and their </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">unsigned</font><font face="Times New Roman, Times, Serif" size="3"> variations:</font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table><table cellpadding="0" cellspacing="0" border="0" width="100%"><tr><td height="12"></td></tr><tr><td><table cellspacing="0" width="496" cellpadding="4"><tr><td valign="top"><font face="Times New Roman, Times, Serif" size="2"><i>Type</i></font></td><td valign="top"><table border="0" cellspacing="0" cellpadding="0" width="100%"><tr><td align="center"><font face="Times New Roman, Times, Serif" size="2"><i>Size in Bytes*</i></font></td></tr></table></td><td valign="top"><font face="Times New Roman, Times, Serif" size="2"><i>Minimum Value*</i></font></td><td valign="top"><font face="Times New Roman, Times, Serif" size="2"><i>Maximum Value*</i></font></td></tr><tr><td valign="top"><font face="Courier New, Courier, Mono New, Courier, Mono" size="2">char</font></td><td valign="top"><table border="0" cellspacing="0" cellpadding="0" width="100%"><tr><td align="center"><font face="Times New Roman, Times, Serif" size="2">1</font></td></tr></table></td><td valign="top"><font face="Times New Roman, Times, Serif" size="2">-128</font></td><td valign="top"><font face="Times New Roman, Times, Serif" size="2">127</font></td></tr><tr><td valign="top"><font face="Courier New, Courier, Mono New, Courier, Mono" size="2">unsigned char</font></td><td valign="top"><table border="0" cellspacing="0" cellpadding="0" width="100%"><tr><td align="center"><font face="Times New Roman, Times, Serif" size="2">1</font></td></tr></table></td><td valign="top"><font face="Times New Roman, Times, Serif" size="2">0</font></td><td valign="top"><font face="Times New Roman, Times, Serif" size="2">255</font></td></tr><tr><td valign="top"><font face="Courier New, Courier, Mono New, Courier, Mono" size="2">short</font></td><td valign="top"><table border="0" cellspacing="0" cellpadding="0" width="100%"><tr><td align="center"><font face="Times New Roman, Times, Serif" size="2">2</font></td></tr></table></td><td valign="top"><font face="Times New Roman, Times, Serif" size="2">-32,768</font></td><td valign="top"><font face="Times New Roman, Times, Serif" size="2">32,767</font></td></tr><tr><td valign="top"><font face="Courier New, Courier, Mono New, Courier, Mono" size="2">unsigned short</font></td><td valign="top"><table border="0" cellspacing="0" cellpadding="0" width="100%"><tr><td align="center"><font face="Times New Roman, Times, Serif" size="2">2</font></td></tr></table></td><td valign="top"><font face="Times New Roman, Times, Serif" size="2">0</font></td><td valign="top"><font face="Times New Roman, Times, Serif" size="2">65,535</font></td></tr><tr><td valign="top"><font face="Courier New, Courier, Mono New, Courier, Mono" size="2">int</font></td><td valign="top"><table border="0" cellspacing="0" cellpadding="0" width="100%"><tr><td align="center"><font face="Times New Roman, Times, Serif" size="2">2</font></td></tr></table></td><td valign="top"><font face="Times New Roman, Times, Serif" size="2">-32,768</font></td><td valign="top"><font face="Times New Roman, Times, Serif" size="2">32,767</font></td></tr><tr><td valign="top"><font face="Courier New, Courier, Mono New, Courier, Mono" size="2">unsigned int</font></td><td valign="top"><table border="0" cellspacing="0" cellpadding="0" width="100%"><tr><td align="center"><font face="Times New Roman, Times, Serif" size="2">2</font></td></tr></table></td><td valign="top"><font face="Times New Roman, Times, Serif" size="2">0</font></td><td valign="top"><font face="Times New Roman, Times, Serif" size="2">65,535</font></td></tr><tr><td valign="top"><font face="Courier New, Courier, Mono New, Courier, Mono" size="2">long</font></td><td valign="top"><table border="0" cellspacing="0" cellpadding="0" width="100%"><tr><td align="center"><font face="Times New Roman, Times, Serif" size="2">4</font></td></tr></table></td><td valign="top"><font face="Times New Roman, Times, Serif" size="2">-2,147,483,648</font></td><td valign="top"><font face="Times New Roman, Times, Serif" size="2">2,147,483,647</font></td></tr><tr><td valign="top"><font face="Courier New, Courier, Mono New, Courier, Mono" size="2">unsigned long</font></td><td valign="top"><table border="0" cellspacing="0" cellpadding="0" width="100%"><tr><td align="center"><font face="Times New Roman, Times, Serif" size="2">4</font></td></tr></table></td><td valign="top"><font face="Times New Roman, Times, Serif" size="2">0</font></td><td valign="top"><font face="Times New Roman, Times, Serif" size="2">4,294,967,295</font></td></tr><tr><td colspan="4" valign="top"><font face="Times New Roman, Times, Serif" size="2">* These values are for one particular machine. Your machine's values may be different.</font></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">Most C++ environments provide the header file </font><font face="Courier New, Courier, Mono New, Courier, Mono" size="3">limits.h</font><font face="Times New Roman, Times, Serif" size="3">, from which you can determine the maximum and minimum values for your machine. This</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_503.html">< previous page</a></td> <td align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_504</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_505.html">next page ></a></td> </tr> </table> </body> </html>⌨️ 快捷键说明
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