.\" ident @(#)logical_not.3
.\" Standard Template Library
.\" $$RW_INSERT_HEADER "slyrs.man"
.TH logical_not 3C++ "02 Apr 1998" "Rogue Wave Software" "-"
.ce2
Standard C++ Library   
Copyright 1998, Rogue Wave Software, Inc.   

.SH NAME

\f2logical_not\fP

\ - A unary function object that returns \f2true\fP if its argument is \f2false\fP.



.SH  SYNOPSIS


.br
#include <functional>
.br
template <class T>
.br
struct logical_not : unary_function<T, bool> ;



.SH  DESCRIPTION


logical_not is a unary function object. Its \f2operator()\fP returns \f2true\fP if its argument is \f2false\fP. You can pass a logical_not object to any algorithm that requires a unary function. For example, the replace_if algorithm replaces an element with another value if the result of a unary operation is \f2true\fP.   logical_not is used in that algorithm in the following manner:


.br
vector<int> vec1;
.br
.
.br
.
.br
.
.br
void replace_if(vec1.begin(), vec1.end(),
.RE
.RS 16
logical_not<int>(),1);
.RE

This call to replace_if replaces all zeros in the \f2vec1\fP with \f21\fP.



.SH  INTERFACE


.RE
.RS 0
template <class T>
.br
struct logical_not : unary_function<T, bool> {
.RE
.RS 1
bool operator() (const T&) const;
.RE
.RS 0
};



.SH  WARNINGS


If your compiler does not support default template parameters, you always need to supply the \f2Allocator\fP template argument. For instance, you have to write:

\f2vector<int, allocator<int> >\fP

instead of: 

\f2vector<int>\fP

If your compiler does not support namespaces, then you do not need the using declaration for \f2std\fP.



.SH  SEE ALSO


Function_Objects, unary_function