<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >bcsub</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="BC math 高精度数学函数" HREF="ref.bc.html"><LINK REL="PREVIOUS" TITLE="bcsqrt" HREF="function.bcsqrt.html"><LINK REL="NEXT" TITLE="BCompiler PHP 字节码编译器" HREF="ref.bcompiler.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.bcsqrt.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="ref.bcompiler.html" ACCESSKEY="N" >下一页</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="function.bcsub" ></A >bcsub</H1 ><DIV CLASS="refnamediv" ><A NAME="AEN14479" ></A ><P > (PHP 3, PHP 4, PHP 5)</P >bcsub -- Subtract one arbitrary precision number from another</DIV ><DIV CLASS="refsect1" ><A NAME="AEN14482" ></A ><H2 >说明</H2 >string <B CLASS="methodname" >bcsub</B > ( string left_operand, string right_operand [, int scale] )<BR ></BR ><P > Subtracts the <CODE CLASS="parameter" >right_operand</CODE > from the <CODE CLASS="parameter" >left_operand</CODE >. </P ></DIV ><DIV CLASS="refsect1" ><A NAME="AEN14499" ></A ><H2 >参数</H2 ><P > <P ></P ><DIV CLASS="variablelist" ><DL ><DT ><CODE CLASS="parameter" >left_operand</CODE ></DT ><DD ><P > The left operand, as a string. </P ></DD ><DT ><CODE CLASS="parameter" >right_operand</CODE ></DT ><DD ><P > The right operand, as a string. </P ></DD ><DT ><CODE CLASS="parameter" > scale</CODE ></DT ><DD ><P >This optional parameter is used to set the number of digits after the decimal place in the result. You can also set the global default scale for all functions by using <A HREF="function.bcscale.html" ><B CLASS="function" >bcscale()</B ></A >.</P ></DD ></DL ></DIV > </P ></DIV ><DIV CLASS="refsect1" ><A NAME="AEN14519" ></A ><H2 >返回值</H2 ><P > The result of the substraction, as a string. </P ></DIV ><DIV CLASS="refsect1" ><A NAME="AEN14522" ></A ><H2 >范例</H2 ><TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" CLASS="EXAMPLE" ><TR ><TD ><DIV CLASS="example" ><A NAME="AEN14524" ></A ><P ><B >例 1. <B CLASS="function" >bcsub()</B > example</B ></P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><code><font color="#000000"> <font color="#0000BB"><?php<br /><br />$a </font><font color="#007700">= </font><font color="#DD0000">'1.234'</font><font color="#007700">;<br /></font><font color="#0000BB">$b </font><font color="#007700">= </font><font color="#DD0000">'5'</font><font color="#007700">;<br /><br />echo </font><font color="#0000BB">bcsub</font><font color="#007700">(</font><font color="#0000BB">$a</font><font color="#007700">, </font><font color="#0000BB">$b</font><font color="#007700">); </font><font color="#FF8000">// -3<br /></font><font color="#007700">echo </font><font color="#0000BB">bcsub</font><font color="#007700">(</font><font color="#0000BB">$a</font><font color="#007700">, </font><font color="#0000BB">$b</font><font color="#007700">, </font><font color="#0000BB">4</font><font color="#007700">); </font><font color="#FF8000">// -3.7660<br /><br /></font><font color="#0000BB">?></font> </font> </code></TD ></TR ></TABLE ></DIV ></TD ></TR ></TABLE ></DIV ><DIV CLASS="refsect1" ><A NAME="AEN14528" ></A ><H2 >参见</H2 ><P > <P ></P ><TABLE BORDER="0" ><TBODY ><TR ><TD ><A HREF="function.bcadd.html" ><B CLASS="function" >bcadd()</B ></A ></TD ></TR ></TBODY ></TABLE ><P ></P > </P ></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.bcsqrt.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="ref.bcompiler.html" ACCESSKEY="N" >下一页</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >bcsqrt</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="ref.bc.html" ACCESSKEY="U" >上一级</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >BCompiler PHP 字节码编译器</TD ></TR ></TABLE ></DIV ></BODY ></HTML >