📄 binary_compose.html
字号:
<HTML>
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<META NAME="Author" CONTENT="Zafir Anjum">
<TITLE>MFC Programmer's SourceBook : STL Programmer's Guide</TITLE>
<META name="description"
content="A freely available implementation
of the C++ Standard Template Library, including
hypertext documentation.">
<META name="keywords"
content="generic programming, STL, standard template library">
</HEAD>
<SCRIPT LANGUAGE="JavaScript"><!--
var adcategory = "cpp";
// -->
</SCRIPT>
<body background="../../fancyhome/back.gif" bgcolor="#FFFFFF" >
<SCRIPT LANGUAGE="JavaScript"><!--
var nfrm = location.href.indexOf("_nfrm_");
var validframes = (top.frames.length > 0 && top.frames['ad'] && top.frames['logo'] );
var random = Math.random();
if( !validframes && nfrm == -1 )
{
var dclkPage = "www.codeguru.com/";
if( self.adcategory )
dclkPage += adcategory;
else
dclkPage += "mfc";
document.write('<nolayer><center>');
document.write('<iframe src="http://ad.doubleclick.net/adi/' + dclkPage + ';ord='
+ random + '" width=470 height=62 marginwidth=0 marginheight=0 hspace=0 vspace=0 '
+ 'frameborder=0 scrolling=no bordercolor="#000000">');
document.write('<a href="http://ad.doubleclick.net/jump/' + dclkPage + ';ord='
+ random + '">');
document.write('<img src="http://ad.doubleclick.net/ad/' + dclkPage + ';ord='
+ random + '" height=60 width=468>' + '</a>');
document.write('</iframe>');
document.write('</center></nolayer>');
document.write('<layer src="http://ad.doubleclick.net/adl/' + dclkPage +
';ord=' + random + '"></layer>');
document.write('<ilayer visibility=hide width=468 height=83></ilayer>');
}
// top.location = "/show.cgi?" + adcategory + "=" + location.pathname;
// -->
</SCRIPT>
<noscript>
<p align="center">
<a href="http://ad.doubleclick.net/jump/www.codeguru.com/cpp;ord=Nupb4dFCY34AAHtILhQ">
<img src="http://ad.doubleclick.net/ad/www.codeguru.com/cpp;ord=Nupb4dFCY34AAHtILhQ"></a>
</p>
</noscript>
<BR Clear>
<H1>binary_compose<AdaptableBinaryFunction,AdaptableUnaryFunction1,AdaptableUnaryFunction2></H1>
<Table CellPadding=0 CellSpacing=0 width=100%>
<TR>
<TD Align=left><Img src = "functors.gif" Alt="" WIDTH = "194" HEIGHT = "38" ></TD>
<TD Align=right><Img src = "type.gif" Alt="" WIDTH = "194" HEIGHT = "39" ></TD>
</TR>
<TR>
<TD Align=left><Img src = "adaptors.gif" Alt="" WIDTH = "194" HEIGHT = "38" ></TD>
<TD Align=right></TD>
</TR>
<TR>
<TD Align=left VAlign=top><b>Categories</b>: functors, adaptors</TD>
<TD Align=right VAlign=top><b>Component type</b>: type</TD>
</TR>
</Table>
<h3>Description</h3>
<tt>Binary_compose</tt> is a <A href="functors.html">function object</A> adaptor.
If <tt>f</tt> is an <A href="AdaptableBinaryFunction.html">Adaptable Binary Function</A> and <tt>g1</tt> and <tt>g2</tt> are both
<A href="AdaptableUnaryFunction.html">Adaptable Unary Functions</A>, and if <tt>g1</tt>'s and <tt>g2</tt>'s return types
are convertible to <tt>f</tt>'s argument types, then <tt>binary_compose</tt> can be
used to create a function object <tt>h</tt> such that <tt>h(x)</tt> is the same as
<tt>f(g1(x), g2(x))</tt>. <A href="#1">[1]</A> <A href="#2">[2]</A>
<h3>Example</h3>
Finds the first element in a list that lies in the range from 1 to 10.
<pre>
<A href="List.html">list</A><int> L;
...
<A href="List.html">list</A><int>::iterator in_range =
<A href="find_if.html">find_if</A>(L.begin(), L.end(),
compose2(<A href="logical_and.html">logical_and</A><bool>(),
<A href="binder2nd.html">bind2nd</A>(<A href="greater_equal.html" tppabs="http://www.sgi.com/Technology/STL/greater_equal.shtml">greater_equal</A><int>(), 1),
<A href="binder2nd.html">bind2nd</A>(<A href="less_equal.html" tppabs="http://www.sgi.com/Technology/STL/less_equal.shtml">less_equal</A><int>(), 10)));
assert(in_range == L.end() || (*in_range >= 1 && *in_range <= 10));
</pre>
<P>
Computes <tt>sin(x)/(x + DBL_MIN)</tt> for each element of a range.
<pre>
<A href="transform.html">transform</A>(first, last, first,
compose2(<A href="divides.html">divides</A><double>(),
<A href="ptr_fun.html">ptr_fun</A>(sin),
<A href="binder2nd.html">bind2nd</A>(<A href="plus.html" tppabs="http://www.sgi.com/Technology/STL/plus.shtml">plus</A><double>(), DBL_MIN)));
</pre>
<h3>Definition</h3>
Defined in <A href="function.h">function.h</A>
<h3>Template parameters</h3>
<Table border>
<TR>
<TH>
Parameter
</TH>
<TH>
Description
</TH>
<TH>
Default
</TH>
</TR>
<TR>
<TD VAlign=top>
<tt>AdaptableBinaryFunction</tt>
</TD>
<TD VAlign=top>
The type of the "outer" function in the function composition
operation. That is, if the <tt>binary_compose</tt> is a function object
<tt>h</tt> such that <tt>h(x) = f(g1(x), g2(x))</tt>, then <tt>AdaptableBinaryFunction</tt>
is the type of <tt>f</tt>.
</TD>
<TD VAlign=top>
</TD>
</TR>
<TR>
<TD VAlign=top>
<tt>AdaptableUnaryFunction1</tt>
</TD>
<TD VAlign=top>
The type of the first "inner" function in the function composition
operation. That is, if the <tt>binary_compose</tt> is a function object
<tt>h</tt> such that <tt>h(x) = f(g1(x), g2(x))</tt>, then <tt>AdaptableBinaryFunction</tt>
is the type of <tt>g1</tt>.
</TD>
<TD VAlign=top>
</TD>
</TR>
<TR>
<TD VAlign=top>
<tt>AdaptableUnaryFunction2</tt>
</TD>
<TD VAlign=top>
The type of the second "inner" function in the function composition
operation. That is, if the <tt>binary_compose</tt> is a function object
<tt>h</tt> such that <tt>h(x) = f(g1(x), g2(x))</tt>, then <tt>AdaptableBinaryFunction</tt>
is the type of <tt>g2</tt>.
</TD>
<TD VAlign=top>
</TD>
</tr>
</table>
<h3>Model of</h3>
<A href="AdaptableUnaryFunction.html">Adaptable Unary Function</A>
<h3>Type requirements</h3>
<tt>AdaptableBinaryFunction</tt> must be a model of <A href="AdaptableBinaryFunction.html">Adaptable Binary Function</A>.
<tt>AdaptableUnaryFunction1</tt> and <tt>AdaptableUnaryFunction2</tt> must both
be models of <A href="AdaptableUnaryFunction.html">Adaptable Unary Function</A>.
The argument types of <tt>AdaptableUnaryFunction1</tt> and
<tt>AdaptableUnaryFunction2</tt> must be convertible to each other.
The result types of <tt>AdaptableUnaryFunction1</tt> and
<tt>AdaptableUnaryFunction2</tt> must be convertible, respectively, to
the first and second argument types of <tt>AdaptableBinaryFunction</tt>.
<h3>Public base classes</h3>
<pre>
<A href="unary_function.html">unary_function</A><AdaptableUnaryFunction1::argument_type,
AdaptableBinaryFunction::result_type>
</pre>
<h3>Members</h3>
<Table border>
<TR>
<TH>
Member
</TH>
<TH>
Where defined
</TH>
<TH>
Description
</TH>
</TR>
<TR>
<TD VAlign=top>
<tt>argument_type</tt>
</TD>
<TD VAlign=top>
<A href="AdaptableUnaryFunction.html">Adaptable Unary Function</A>
</TD>
<TD VAlign=top>
The type of the function object's argument:
<tt>AdaptableUnaryFunction::argument_type</tt>.
</TD>
</TR>
<TR>
<TD VAlign=top>
<tt>result_type</tt>
</TD>
<TD VAlign=top>
<A href="AdaptableUnaryFunction.html">Adaptable Unary Function</A>
</TD>
<TD VAlign=top>
The type of the result: <tt>AdaptableBinaryFunction::result_type</tt>
</TD>
</TR>
<TR>
<TD VAlign=top>
<pre>
binary_compose(const AdaptableBinaryFunction& f,
const AdaptableUnaryFunction1& g1,
const AdaptableUnaryFunction1& g2);
</pre>
</TD>
<TD VAlign=top>
<tt>binary_compose</tt>
</TD>
<TD VAlign=top>
See below.
</TD>
</TR>
<TR>
<TD VAlign=top>
<pre>
template <class <A href="AdaptableBinaryFunction.html">AdaptableBinaryFunction</A>,
class <A href="AdaptableUnaryFunction.html">AdaptableUnaryFunction</A>1,
class <A href="AdaptableUnaryFunction.html">AdaptableUnaryFunction</A>2>
binary_compose<AdaptableBinaryFunction,
AdaptableUnaryFunction1,
AdaptableUnaryFunction2>
compose2(const AdaptableBinaryFunction&,
const AdaptableUnaryFunction1&,
const AdaptableUnaryFunction2&);
</pre>
</TD>
<TD VAlign=top>
<tt>binary_compose</tt>
</TD>
<TD VAlign=top>
See below.
</TD>
</tr>
</table>
<h3>New members</h3>
These members are not defined in the
<A href="AdaptableUnaryFunction.html">Adaptable Unary Function</A>
requirements, but are specific to
<tt>binary_compose</tt>.
<Table border>
<TR>
<TH>
Member
</TH>
<TH>
Description
</TH>
</TR>
<TR>
<TD VAlign=top>
<pre>
binary_compose(const AdaptableBinaryFunction& f,
const AdaptableUnaryFunction1& g1,
const AdaptableUnaryFunction1& g2);
</pre>
</TD>
<TD VAlign=top>
The constructor. Constructs a <tt>binary_compose</tt> object such that
calling that object with the argument <tt>x</tt> returns
<tt>f(g1(x), g2(x))</tt>.
</TD>
</TR>
<TR>
<TD VAlign=top>
<pre>
template <class <A href="AdaptableBinaryFunction.html">AdaptableBinaryFunction</A>,
class <A href="AdaptableUnaryFunction.html">AdaptableUnaryFunction</A>1,
class <A href="AdaptableUnaryFunction.html">AdaptableUnaryFunction</A>2>
binary_compose<AdaptableBinaryFunction,
AdaptableUnaryFunction1,
AdaptableUnaryFunction2>
compose2(const AdaptableBinaryFunction&,
const AdaptableUnaryFunction1&,
const AdaptableUnaryFunction2&);
</pre>
</TD>
<TD VAlign=top>
Creates a <tt>binary_compose</tt> object. If <tt>f</tt>, <tt>g</tt>, and <tt>g2</tt> are, respectively,
of classes <tt>AdaptableBinaryFunction</tt>, <tt>AdaptableUnaryFunction1</tt>, and
<tt>AdaptableUnaryFunction2</tt>, then <tt>compose2(f, g1, g2)</tt> is equivalent to
<tt>binary_compose<AdaptableBinaryFunction, AdaptableUnaryFunction1,
AdaptableUnaryFunction2>(f, g1, g2)</tt>, but is more convenient.
This is a global function, not a member function.
</TD>
</tr>
</table>
<h3>Notes</h3>
<P><A name="1">[1]</A>
This is a form of function composition. The <tt><A href="unary_compose.html">unary_compose</A></tt>
adaptor allows composition of <A href="AdaptableUnaryFunction.html">Adaptable Unary Functions</A>; note,
however, that once binary functions are introduced, there are several
possible patterns of function composition. The <tt>binary_compose</tt>
allows you to form a unary function by putting together two unary
functions and a binary function, but you could also, for example,
imagine putting together two unary functions and a binary function to
form a binary function. In that case, <tt>f</tt>, <tt>g1</tt>, and <tt>g2</tt> would be
combined into a function object <tt>h</tt> such that <tt>h(x,y) = f(g1(x),
g2(y))</tt>.
<h3>See also</h3>
The <A href="functors.html">function object overview</A>, <tt><A href="unary_compose.html" tppabs="http://www.sgi.com/Technology/STL/unary_compose.shtml">unary_compose</A></tt>,
<tt><A href="binder1st.html">binder1st</A></tt>, <tt><A href="binder2nd.html" tppabs="http://www.sgi.com/Technology/STL/binder2nd.shtml">binder2nd</A></tt>.
<HR SIZE="6"> <FONT SIZE="-2"> Copyright © 1996 Silicon Graphics, Inc.
<HR>
<TABLE BORDER=0 WIDTH="100%" >
<TR>
<TD WIDTH="33%"><FONT SIZE=-1><A HREF="index.html" >
STL</A></FONT></TD>
<TD WIDTH="33%">
<CENTER><FONT SIZE=-2>© Copyright 1997-1998 CodeGuru</FONT> </CENTER>
</TD>
<TD WIDTH="34%">
<DIV ALIGN=right><FONT SIZE=-1>Contact : <A HREF="mailto:webmaster@codeguru.com">webmaster@codeguru.com</A> </FONT></DIV>
</TD>
</TR>
</TABLE>
<SCRIPT LANGUAGE="JavaScript" ><!--
var adurl = "/cgi-bin/doubleclick.cgi?";
if( self.adcategory )
adurl += adcategory;
else
adurl += "mfc";
if( self.parent.norefreshad )
parent.norefreshad = false;
else if( validframes )
parent.frames['ad'].location = adurl;
if( !validframes && nfrm == -1)
{
var dclkPage = "www.codeguru.com/";
if( self.adcategory )
dclkPage += adcategory;
else
dclkPage += "mfc";
// var random = Math.random();
document.write('<nolayer><center>');
document.write('<iframe src="http://ad.doubleclick.net/adi/' + dclkPage + ';ord='
+ random + '" width=470 height=62 marginwidth=0 marginheight=0 hspace=0 vspace=0 '
+ 'frameborder=0 scrolling=no bordercolor="#000000">');
document.write('<a href="http://ad.doubleclick.net/jump/' + dclkPage + ';ord='
+ random + '">');
document.write('<img src="http://ad.doubleclick.net/ad/' + dclkPage + ';ord='
+ random + '" height=60 width=468>' + '</a>');
document.write('</iframe>');
document.write('</center></nolayer>');
document.write('<layer src="http://ad.doubleclick.net/adl/' + dclkPage +
';ord=' + random + '"></layer>');
document.write('<ilayer visibility=hide width=468 height=83></ilayer>');
}
// -->
</SCRIPT>
<!-- SCRIPT LANGUAGE="JavaScript" SRC="/global/fscript.js">
//
</SCRIPT -->
<noscript>
<p align="center">
<a href="http://ad.doubleclick.net/jump/www.codeguru.com/cpp;ord=Nupb4dFCY34AAHtILhQ">
<img src="http://ad.doubleclick.net/ad/www.codeguru.com/cpp;ord=Nupb4dFCY34AAHtILhQ"></a>
</p>
</noscript>
</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 + -