<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >gmp_nextprime</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REL="HOME" TITLE="PHP 手册" HREF="index.html"><LINK REL="UP" TITLE="GMP Functions" HREF="ref.gmp.html"><LINK REL="PREVIOUS" TITLE="gmp_neg" HREF="function.gmp-neg.html"><LINK REL="NEXT" TITLE="gmp_or" HREF="function.gmp-or.html"><META HTTP-EQUIV="Content-type" CONTENT="text/html; charset=UTF-8"></HEAD ><BODY CLASS="refentry" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >PHP 手册</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="function.gmp-neg.html" ACCESSKEY="P" >上一页</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="function.gmp-or.html" ACCESSKEY="N" >下一页</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="function.gmp-nextprime" ></A >gmp_nextprime</H1 ><DIV CLASS="refnamediv" ><A NAME="AEN64741" ></A ><P > (no version information, might be only in CVS)</P >gmp_nextprime -- Find next prime number</DIV ><DIV CLASS="refsect1" ><A NAME="AEN64744" ></A ><H2 >Description</H2 >resource <B CLASS="methodname" >gmp_nextprime</B > ( int a )<BR ></BR ><P > Return next prime number greater than <CODE CLASS="parameter" >a</CODE >. </P ><P > This function uses a probabilistic algorithm to identify primes and chances to get a composite number are extremely small. </P ><TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" CLASS="EXAMPLE" ><TR ><TD ><DIV CLASS="example" ><A NAME="AEN64755" ></A ><P ><B >例 1. <B CLASS="function" >gmp_nextprime()</B > example</B ></P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><code><font color="#000000"> <font color="#0000BB"><?php<br />$prime1 </font><font color="#007700">= </font><font color="#0000BB">gmp_nextprime</font><font color="#007700">(</font><font color="#0000BB">10</font><font color="#007700">); </font><font color="#FF8000">// next prime number greater than 10<br /></font><font color="#0000BB">$prime2 </font><font color="#007700">= </font><font color="#0000BB">gmp_nextprime</font><font color="#007700">(-</font><font color="#0000BB">1000</font><font color="#007700">); </font><font color="#FF8000">// next prime number greater than -1000<br /><br /></font><font color="#007700">echo </font><font color="#0000BB">gmp_strval</font><font color="#007700">(</font><font color="#0000BB">$prime1</font><font color="#007700">) . </font><font color="#DD0000">"\n"</font><font color="#007700">;<br />echo </font><font color="#0000BB">gmp_strval</font><font color="#007700">(</font><font color="#0000BB">$prime2</font><font color="#007700">) . </font><font color="#DD0000">"\n"</font><font color="#007700">;<br /></font><font color="#0000BB">?></font> </font> </code></TD ></TR ></TABLE ><P > The printout of the above program is: </P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><PRE CLASS="screen" >11 -997</PRE ></TD ></TR ></TABLE ></DIV ></TD ></TR ></TABLE ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="function.gmp-neg.html" ACCESSKEY="P" >上一页</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >起始页</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="function.gmp-or.html" ACCESSKEY="N" >下一页</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >gmp_neg</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="ref.gmp.html" ACCESSKEY="U" >上一级</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >gmp_or</TD ></TR ></TABLE ></DIV ></BODY ></HTML >