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  26. <div class="titlepage"><div><div><h3 class="title">
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  27. <a name="phoenix.starter_kit.arguments"></a><a class="link" href="arguments.html" title="Arguments">Arguments</a>
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  29. <p>
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  30.         Arguments are also functions? You bet!
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  31.       </p>
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  33.         Until now, we have been dealing with expressions returning a nullary function.
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  34.         Arguments, on the other hand, evaluate to an N-ary function. An argument
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  35.         represents the Nth argument. There are a few predefined arguments arg1, arg2,
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  36.         arg3, arg4 and so on (and it's <a href="http://www.boost.org/libs/lambda/doc/index.html" target="_top">BLL</a>
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  37.         counterparts: _1, _2, _3, _4 and so on). Examples:
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  38.       </p>
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  39. <pre class="programlisting"><span class="identifier">arg1</span> <span class="comment">// one-or-more argument function that returns its first argument
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  40. </span><span class="identifier">arg2</span> <span class="comment">// two-or-more argument function that returns its second argument
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  41. </span><span class="identifier">arg3</span> <span class="comment">// three-or-more argument function that returns its third argument
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  42. </span></pre>
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  43. <p>
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  44.         <code class="computeroutput"><span class="identifier">argN</span></code> returns the Nth argument.
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  45.         Examples:
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  46.       </p>
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  47. <pre class="programlisting"><span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">3</span><span class="special">;</span>
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  48. <span class="keyword">char</span> <span class="keyword">const</span><span class="special">*</span> <span class="identifier">s</span> <span class="special">=</span> <span class="string">"Hello World"</span><span class="special">;</span>
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  49. <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">arg1</span><span class="special">(</span><span class="identifier">i</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>        <span class="comment">// prints 3
    50. 

  50. </span><span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">arg2</span><span class="special">(</span><span class="identifier">i</span><span class="special">,</span> <span class="identifier">s</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>     <span class="comment">// prints "Hello World"
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  51. </span></pre>
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  53.         (See <a href="../../../../example/arguments.cpp" target="_top">arguments.cpp</a>)
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  57. <p>
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  58.         <span class="inlinemediaobject"><img src="../../images/tip.png" alt="tip"></span> Learn more about arguments <a class="link" href="../modules/core/arguments.html" title="Arguments">here.</a>
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  64. <td align="right"><div class="copyright-footer">Copyright &#169; 2002-2005, 2010 Joel de Guzman, Dan Marsden, Thomas Heller<p>
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