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PORecursive templates don't work as expected with static variables
 

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  1. PORecursive templates don't work as expected with static variables
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    <p>The code</p> <pre class="lang-cpp prettyprint-override"><code>#include &lt;iostream&gt; using namespace std; template&lt;int n&gt; struct Fibo { static int x; }; template&lt;&gt; int Fibo&lt;0&gt;::x = 1; template&lt;&gt; int Fibo&lt;1&gt;::x = 1; template&lt;int n&gt; int Fibo&lt;n&gt;::x = Fibo&lt;n-1&gt;::x + Fibo&lt;n-2&gt;::x; //marked line int main() { cout &lt;&lt; Fibo&lt;5&gt;::x &lt;&lt; endl; cout &lt;&lt; Fibo&lt;4&gt;::x &lt;&lt; endl; cout &lt;&lt; Fibo&lt;3&gt;::x &lt;&lt; endl; cout &lt;&lt; Fibo&lt;2&gt;::x &lt;&lt; endl; cout &lt;&lt; Fibo&lt;1&gt;::x &lt;&lt; endl; cout &lt;&lt; Fibo&lt;0&gt;::x &lt;&lt; endl; return 0; } </code></pre> <p>outputs</p> <pre class="lang-cpp prettyprint-override"><code>0 0 1 2 1 1 </code></pre> <p>in VC++. (According to user <a href="https://stackoverflow.com/users/952747/m-m">M M.</a> it compiles as expected in gcc). When the compiler gets to the marked line with <code>n=5</code> it doesn't compile that same line again for <code>n=4</code>, but just treats <code>Fibo&lt;4&gt;::x</code> as if it were declared with</p> <pre class="lang-cpp prettyprint-override"><code>template&lt;&gt; int Fibo&lt;4&gt;::x; // x defaults to 0 </code></pre> <p>Why is that? Why does it work as expected when using</p> <pre class="lang-cpp prettyprint-override"><code>template&lt;int n&gt; struct Fibo { enum { x = Fibo&lt;n-1&gt;::x + Fibo&lt;n-2&gt;::x }; }; template&lt;&gt; struct Fibo&lt;0&gt; { enum { x = 1 }; }; template&lt;&gt; struct Fibo&lt;1&gt; { enum { x = 1 }; }; </code></pre> <p>instead, but not with a static variable? And how do you fix the first code (without <code>enum</code>)?</p>
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    1. COIt compiles fine in `gcc-4.8.0` and output is `"8 5 3 2 1 1"`.
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    2. CONice, I never knew you could specialize static member initializers.
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    3. COThanks, M M. I'll add a note saying I used VC++.
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