.\" ident	@(#)Array_alg:man/rt_pos.3	3.2
.\"
.\" C++ Standard Components, Release 3.0.
.\"
.\" Copyright (c) 1991, 1992 AT&T and UNIX System Laboratories, Inc.
.\" Copyright (c) 1988, 1989, 1990 AT&T.  All Rights Reserved.
.\"
.\" THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF AT&T and UNIX System
.\" Laboratories, Inc.  The copyright notice above does not evidence
.\" any actual or intended publication of such source code.
.\" 
.TH \f3rt_pos\fP \f3Array_alg(3C++)\fP " "
.SH NAME
rt_pos \- find the rightmost element in an array satisfying a given criterion
.SH SYNOPSIS OF Array_alg.h
.Bf

    template <class \*(gt>
    const \*(gt* rt_pos(
	const \*(gt& val,
	const \*(gt* b,
	const \*(gt* e
    );
    template <class \*(gt>
    const \*(gt* rt_pos_p(
        int (*pred)(const \*(gt*),
	const \*(gt* b,
	const \*(gt* e
    );
    template <class \*(gt>
    const \*(gt* rt_pos_r(
        int (*rel)(const \*(gt*,const \*(gt*),
	const \*(gt& val,
	const \*(gt* b,
	const \*(gt* e
    );
.Be
.SH ASSUMPTIONS
.PP
(1) For the plain version, \*(gt\f4::operator==\f1
defines an equivalence relation on \*(gt
.br
(2) For the relational version, \f4rel\f1
defines an equivalence relation on \*(gt
.SH DESCRIPTION
.PP
These functions return a pointer to the rightmost element
satisfying some criterion.  If no such element can be
found, they return \f20\f1.
.sp 0.5v
.IP "\f4template <class \*(gt>\f1"
.IC "\f4const \*(gt* rt_pos(\f1"
.IC "\f4    const \*(gt& val,\f1"
.IC "\f4    const \*(gt* b,\f1"
.IC "\f4    const \*(gt* e\f1"
.IC "\f4);\f1"
Uses equality with \f4val\f1 as the criterion,
with \f4\*(gt::operator==\f1 used for equality.
.IP "\f4template <class \*(gt>\f1"
.IC "\f4const \*(gt* rt_pos_p(\f1"
.IC "\f4    int (*pred)(const \*(gt),\f1"
.IC "\f4    const \*(gt* b,\f1"
.IC "\f4    const \*(gt* e\f1"
.IC "\f4);\f1"
Uses the predicate \f4pred\f1 as the criterion.
That is, if \f4p\f1 is a pointer into the array,
then \f4*p\f1 satisfies the criterion if \f4pred(p)\f1
is true.
.IP "\f4template <class \*(gt>\f1"
.IC "\f4const \*(gt* rt_pos_r(\f1"
.IC "\f4    int (*rel)(const \*(gt*, const \*(gt),\f1"
.IC "\f4    const \*(gt& val,\f1"
.IC "\f4    const \*(gt* b,\f1"
.IC "\f4    const \*(gt* e\f1"
.IC "\f4);\f1"
Like \f4rt_pos\f1 except that \f4rel\f1 is used
for the equality test.  
.SH COMPLEXITY
.PP
If \f2N\f1 is the size of the array,
then complexity is \f2O(N)\f1.
At most N equality tests are done.
.SH NOTES
Because a Block (see \f3Block(3C++)\f1)
can always be used wherever an array is called for,
Array Algorithms can also be used with Blocks.
In fact, these two components were actually designed 
to be used together.
.SH SEE ALSO
.Bf
\f3intro(.)\f1
\f3pos(.)\f1
\f3Block(3C++)\f1
.Be