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<H1>logical_or<T></H1>
<Table CellPadding=0 CellSpacing=0 width=100%>
<TR>
<TD Align=left><Img src = "functors.gif" Alt="" WIDTH = "194" HEIGHT = "38" ></TD>
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<TR>
<TD Align=left VAlign=top><b>Category</b>: functors</TD>
<TD Align=right VAlign=top><b>Component type</b>: type</TD>
</TR>
</Table>
<h3>Description</h3>
<tt>Logical_or<T></tt> is a <A href="functors.html">function object</A>; specifically, it is an
<A href="AdaptableBinaryPredicate.html">Adaptable Binary Predicate</A>, which means it is a function
object that tests the truth or falsehood of some condition.
If <tt>f</tt> is an object of class <tt>logical_and<T></tt>
and <tt>x</tt> and <tt>y</tt> are objects of class <tt>T</tt> (where <tt>T</tt> is convertible
to <tt>bool</tt>) then <tt>f(x,y)</tt> returns true if and only if either <tt>x</tt> or
<tt>y</tt> is <tt>true</tt>. <A href="#1">[1]</A>
<h3>Example</h3>
Finds the first instance of either ' ' or '\n' in a string.
<pre>
char str[MAXLEN];
...
const char* wptr = <A href="find_if.html">find_if</A>(str, str + MAXLEN,
<A href="binary_compose.html">compose2</A>(logical_or<bool>(),
<A href="binder2nd.html">bind2nd</A>(<A href="equal_to.html" tppabs="http://www.sgi.com/Technology/STL/equal_to.shtml">equal_to</A><char>(), ' '),
<A href="binder2nd.html">bind2nd</A>(<A href="equal_to.html" tppabs="http://www.sgi.com/Technology/STL/equal_to.shtml">equal_to</A><char>(), '\n')));
assert(wptr == str + MAXLEN || *wptr == ' ' || *wptr == '\n');
</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>T</tt>
</TD>
<TD VAlign=top>
The type of <tt>logical_or</tt>'s arguments
</TD>
<TD VAlign=top>
</TD>
</tr>
</table>
<h3>Model of</h3>
<A href="AdaptableBinaryPredicate.html">Adaptable Binary Predicate</A>, <A href="DefaultConstructible.html" tppabs="http://www.sgi.com/Technology/STL/DefaultConstructible.shtml">DefaultConstructible</A>
<h3>Type requirements</h3>
<tt>T</tt> must be convertible to <tt>bool</tt>.
<h3>Public base classes</h3>
<tt><A href="binary_function.html">binary_function</A><T, T, bool></tt>
<h3>Members</h3>
<Table border>
<TR>
<TH>
Member
</TH>
<TH>
Where defined
</TH>
<TH>
Description
</TH>
</TR>
<TR>
<TD VAlign=top>
<tt>first_argument_type</tt>
</TD>
<TD VAlign=top>
<A href="AdaptableBinaryFunction.html">Adaptable Binary Function</A>
</TD>
<TD VAlign=top>
The type of the first argument: <tt>T</tt>
</TD>
</TR>
<TR>
<TD VAlign=top>
<tt>second_argument_type</tt>
</TD>
<TD VAlign=top>
<A href="AdaptableBinaryFunction.html">Adaptable Binary Function</A>
</TD>
<TD VAlign=top>
The type of the second argument: <tt>T</tt>
</TD>
</TR>
<TR>
<TD VAlign=top>
<tt>result_type</tt>
</TD>
<TD VAlign=top>
<A href="AdaptableBinaryFunction.html">Adaptable Binary Function</A>
</TD>
<TD VAlign=top>
The type of the result: <tt>bool</tt>
</TD>
</TR>
<TR>
<TD VAlign=top>
<tt>bool operator()(const T& x, const T& y) const</tt>
</TD>
<TD VAlign=top>
<A href="BinaryFunction.html">Binary Function</A>
</TD>
<TD VAlign=top>
Function call operator. The return value is <tt>x || y</tt>.
</TD>
</TR>
<TR>
<TD VAlign=top>
<tt>logical_or()</tt>
</TD>
<TD VAlign=top>
<A href="DefaultConstructible.html">Default Constructible</A>
</TD>
<TD VAlign=top>
The default constructor.
</TD>
</tr>
</table>
<h3>New members</h3>
All of <tt>logical_or</tt>'s members are defined in the
<A href="AdaptableBinaryFunction.html">Adaptable Binary Function</A> and <A href="DefaultConstructible.html" tppabs="http://www.sgi.com/Technology/STL/DefaultConstructible.shtml">Default Constructible</A>
requirements.
<tt>Logical_or</tt> does not introduce any new members.
<h3>Notes</h3>
<P><A name="1">[1]</A>
<tt><A href="logical_and.html">Logical_and</A></tt> and <tt>logical_or</tt> are not very useful by themselves.
They are mainly useful because, when combined with the function object
adaptor <tt><A href="binary_compose.html">binary_compose</A></tt>, they perform logical operations on other
function objects.
<h3>See also</h3>
The <A href="functors.html">function object overview</A>, <tt><A href="logical_and.html" tppabs="http://www.sgi.com/Technology/STL/logical_and.shtml">logical_and</A></tt>, <tt><A href="logical_not.html" tppabs="http://www.sgi.com/Technology/STL/logical_not.shtml">logical_not</A></tt>.
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