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POHow can I write a function template for all types with a particular type trait?
 

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    <p>Consider the following example:</p> <pre><code>struct Scanner { template &lt;typename T&gt; T get(); }; template &lt;&gt; string Scanner::get() { return string("string"); } template &lt;&gt; int Scanner::get() { return 10; } int main() { Scanner scanner; string s = scanner.get&lt;string&gt;(); int i = scanner.get&lt;int&gt;(); } </code></pre> <p>The <code>Scanner</code> class is used to extract tokens from some source. The above code works fine, but fails when I try to <code>get</code> other integral types like a <code>char</code> or an <code>unsigned int</code>. The code to read these types is exactly the same as the code to read an <code>int</code>. I could just duplicate the code for all other integral types I'd like to read, but I'd rather define one function template for all integral types.</p> <p>I've tried the following:</p> <pre><code>struct Scanner { template &lt;typename T&gt; typename enable_if&lt;boost::is_integral&lt;T&gt;, T&gt;::type get(); }; </code></pre> <p>Which works like a charm, but I am unsure how to get <code>Scanner::get&lt;string&gt;()</code> to function again. So, how can I write code so that I can do <code>scanner.get&lt;string&gt;()</code> and <code>scanner.get&lt;any integral type&gt;()</code> and have a single definition to read all integral types?</p> <p><strong>Update: bonus question</strong>: What if I want to accept more than one range of classes based on some traits? For example: how should I approach this problem if I want to have three <code>get</code> functions that accept (i) integral types (ii) floating point types (iii) strings, respectively.</p>
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