📄 ch08_142.htm
字号:
<html><head><title>Math::BigFloat (Perl in a Nutshell, 2nd Edition)</title><link rel="stylesheet" type="text/css" href="../style/style1.css" /><meta name="DC.Creator" content="Stephen Spainhour" /><meta name="DC.Format" content="text/xml" scheme="MIME" /><meta name="DC.Language" content="en-US" /><meta name="DC.Publisher" content="O'Reilly & Associates, Inc." /><meta name="DC.Source" scheme="ISBN" content="0596002416L" /><meta name="DC.Subject.Keyword" content="stuff" /><meta name="DC.Title" content="Perl in a Nutshell, 2nd Edition" /><meta name="DC.Type" content="Text.Monograph" /></head><body bgcolor="#ffffff"><img src="gifs/smbanner.gif" usemap="#banner-map" border="0" alt="Book Home" /><map name="banner-map"><area shape="rect" coords="1,-2,616,66" href="index.htm" alt="Java and XSLT" /><area shape="rect" coords="629,-11,726,25" href="jobjects/fsearch.htm" alt="Search this book" /></map><div class="navbar"><table width="684" border="0"><tr><td align="left" valign="top" width="228"><a href="ch08_141.htm"><img src="../gifs/txtpreva.gif" alt="Previous" border="0" /></a></td><td align="center" valign="top" width="228" /><td align="right" valign="top" width="228"><a href="ch08_143.htm"><img src="../gifs/txtnexta.gif" alt="Next" border="0" /></a></td></tr></table></div><h2 class="sect1">8.142. Math::BigFloat</h2><p><a name="INDEX-1495" /><a name="INDEX-1496" />Provides methods that permit use offloating-point numbers of arbitrary length. The following apply toall methods, except as noted:</p><ul><li><p>The object <tt class="literal">$</tt><em class="replaceable"><tt>f</tt></em> remainsunchanged.</p></li><li><p>All methods except <tt class="literal">fcmp</tt> return a number string(<em class="replaceable"><tt>nstr</tt></em>) of the form<tt class="literal">/[+-]\d+E[+-]\d+/</tt>, with embedded whitespaceignored.</p></li><li><p>A return value of <tt class="literal">NaN</tt> indicates that either aninput parameter was "Not a Number"or that an illegal operation was attempted.</p></li><li><p>A similar default scale value is computed for square roots.</p></li></ul><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>new</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">f</em> = Math::BigFloat->new(<em class="replaceable">string</em>)</pre><p>Creates a new object,<tt class="literal">$</tt><em class="replaceable"><tt>f</tt></em>.</p></div><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>fabs</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">f</em>->fabs( )</pre><p>Returns absolute value of<tt class="literal">$</tt><em class="replaceable"><tt>f</tt></em>.</p></div><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>fadd</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">f</em>->fadd(<em class="replaceable">nstr</em>)</pre><p>Returns sum of <em class="replaceable">nstr</em> and<tt class="literal">$</tt><em class="replaceable"><tt>f</tt></em>.</p></div><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>fcmp</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">f</em>->fcmp(<em class="replaceable">nstr</em>)</pre><p>Compares <tt class="literal">$</tt><em class="replaceable">f</em> to<em class="replaceable"><tt>nstr</tt></em>. Returns <tt class="literal">-1</tt>,<tt class="literal">0</tt>, or <tt class="literal">1</tt> depending on whether<tt class="literal">$</tt><em class="replaceable"><tt>f</tt></em> is less than, equalto, or greater than <em class="replaceable"><tt>nstr</tt></em>, or<tt class="literal">undef</tt> if <em class="replaceable"><tt>nstr</tt></em> is not anumber.</p></div><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>fdiv</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">f</em>->fdiv(<em class="replaceable">nstr</em>[,<em class="replaceable">n</em>])</pre><p>Returns <tt class="literal">$</tt><em class="replaceable">f</em> divided by<em class="replaceable"><tt>nstr</em> to <em class="replaceable">n</em>places. If <em class="emphasis">scale</tt></em> (the number of digits) isunspecified, division is computed to the number of digits given by:</p><blockquote><pre class="code">max($div_scale, length(dividend)+length(divisor))</pre></blockquote></div><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>ffround</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">f</em>->ffround(<em class="replaceable">n</em>)</pre><p>Returns <tt class="literal">$</tt><em class="replaceable">f </em>rounded at<em class="replaceable"><tt>n</tt></em>th place.</p></div><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>fmul</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">f</em><em class="replaceable">->fmul</em>(<em class="replaceable">nstr</em>)</pre><p>Returns <tt class="literal">$</tt><em class="replaceable">f</em> multipliedby <em class="replaceable"><tt>nstr</tt></em>.</p></div><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>fneg</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">f</em>->fneg( )</pre><p>Returns negative of <tt class="literal">$</tt><em class="replaceable">f</em>.</p></div><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>fnorm</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">f</em>->fnorm( )</pre><p>Returns normalization of<tt class="literal">$</tt><em class="replaceable"><tt>f</tt></em>.</p></div><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>fround</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">f</em>->fround(<em class="replaceable">n</em>)</pre><p>Returns value of <tt class="literal">$</tt><em class="replaceable">f</em>rounded to <em class="replaceable">n</em> digits.</p></div><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>fsqrt</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">f</em>->fsqrt([<em class="replaceable">n</em>])</pre><p>Returns square root of<tt class="literal">$</tt><em class="replaceable"><tt>f</tt></em> to<em class="replaceable"><tt>n</tt></em> places.</p></div><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>fsub</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">f</em>->fsub(<em class="replaceable">nstr</em>)</pre><p>Returns <tt class="literal">$</tt><em class="replaceable">f</em> minus<em class="replaceable"><tt>nstr</tt></em>.</p></div><hr width="684" align="left" /><div class="navbar"><table width="684" border="0"><tr><td align="left" valign="top" width="228"><a href="ch08_141.htm"><img src="../gifs/txtpreva.gif" alt="Previous" border="0" /></a></td><td align="center" valign="top" width="228"><a href="index.htm"><img src="../gifs/txthome.gif" alt="Home" border="0" /></a></td><td align="right" valign="top" width="228"><a href="ch08_143.htm"><img src="../gifs/txtnexta.gif" alt="Next" border="0" /></a></td></tr><tr><td align="left" valign="top" width="228">8.141. locale</td><td align="center" valign="top" width="228"><a href="index/index.htm"><img src="../gifs/index.gif" alt="Book Index" border="0" /></a></td><td align="right" valign="top" width="228">8.143. Math::BigInt</td></tr></table></div><hr width="684" align="left" /><img src="../gifs/navbar.gif" usemap="#library-map" border="0" alt="Library Navigation Links" /><p><p><font size="-1"><a href="copyrght.htm">Copyright © 2002</a> O'Reilly & Associates. All rights reserved.</font></p><map name="library-map"><area shape="rect" coords="1,0,85,94" href="../index.htm"><area shape="rect" coords="86,1,178,103" href="../lwp/index.htm"><area shape="rect" coords="180,0,265,103" href="../lperl/index.htm"><area shape="rect" coords="267,0,353,105" href="../perlnut/index.htm"><area shape="rect" coords="354,1,446,115" href="../prog/index.htm"><area shape="rect" coords="448,0,526,132" href="../tk/index.htm"><area shape="rect" coords="528,1,615,119" href="../cookbook/index.htm"><area shape="rect" coords="617,0,690,135" href="../pxml/index.htm"></map></body></html>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -