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    copied!<p>I'm not sure if the initialization order of the <em>static variables</em> of <code>template&lt;int n&gt; int Fibo&lt;n&gt;::x = Fibo&lt;n-1&gt;::x + Fibo&lt;n-2&gt;::x;</code> is specified...</p> <p>You may write this:</p> <pre><code>template &lt;int N&gt; struct Fibo { int operator()() const { static int x = Fibo&lt;N - 1&gt;()() + Fibo&lt;N - 2&gt;()(); return x; } }; template &lt;&gt; struct Fibo&lt;1&gt; { int operator()() const { static int x = 1; return x; } }; template &lt;&gt; struct Fibo&lt;0&gt; { int operator()() const { static int x = 1; return x; } }; </code></pre> <p>The dependencies are respected.</p> <p>[Edit]</p> <p>In a case where the value may be modified (according to your comment), you may use similar technique but returning reference:</p> <pre><code>template &lt;int N&gt; struct Fibo { private: int&amp; operator()() { static int x = Fibo&lt;N - 1&gt;()() + Fibo&lt;N - 2&gt;()(); return x; } public: int operator()() const { return const_cast&lt;Fibo&amp;&gt;(*this)(); } // This change Fibo&lt;0&gt; and Fibo&lt;1&gt; and then update value up to Fibo&lt;N&gt;. int operator(int fibo0, int fibo1) { int n_1 = Fibo&lt;N - 1&gt;()(fibo1, fibo2); (*this)() = n_1 + Fibo&lt;N - 2&gt;()(); } }; template &lt;&gt; struct Fibo&lt;1&gt; { private: int&amp; operator()() { static int x = 1; return x; } public: int operator()() const { return const_cast&lt;Fibo&amp;&gt;(*this)(); } void operator(int fibo0, int fibo1) { Fibo&lt;0&gt;()(fibo0); (*this)() = fibo1; } }; template &lt;&gt; struct Fibo&lt;0&gt; { private: int&amp; operator()() { static int x = 1; return x; } public: int operator()() const { return const_cast&lt;Fibo&amp;&gt;(*this)(); } void operator(int fibo0) { (*this)() = fibo0; } }; </code></pre>
 

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