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    copied!<p>To expand on sbi's implementation, here's one that does exponentiation-by-squaring (which requires fewer template instantiations for large powers).</p> <p>Note that if you really only want to calculate powers of 2, you're much better off just left-shifting (i.e., <code>2**x == 1 &lt;&lt; x</code>) rather than doing all this template stuff.</p> <pre><code>#include &lt;iostream&gt; template &lt;unsigned long long N, unsigned int P, int Odd = (P&amp;1)&gt; struct Power; template &lt;unsigned long long N, unsigned int P&gt; struct Power&lt;N,P,0&gt; { // even (square N and halve the power) static const unsigned long long val = Power&lt;N*N,(P/2)&gt;::val; }; template &lt;unsigned long long N, unsigned int P&gt; struct Power&lt;N,P,1&gt; { // odd (multiply by N and decrement the power) static const unsigned long long val = N * Power&lt;N,(P-1)&gt;::val; }; template &lt;unsigned long long N&gt; struct Power&lt;N,0,0&gt; { // zero (x**0 is 1 for all x != 0) static const unsigned long long val = 1; }; int main() { std::cout &lt;&lt; "2**0 = " &lt;&lt; Power&lt;2,0&gt;::val &lt;&lt; "\n"; std::cout &lt;&lt; "2**1 = " &lt;&lt; Power&lt;2,1&gt;::val &lt;&lt; "\n"; std::cout &lt;&lt; "2**2 = " &lt;&lt; Power&lt;2,2&gt;::val &lt;&lt; "\n"; std::cout &lt;&lt; "2**3 = " &lt;&lt; Power&lt;2,3&gt;::val &lt;&lt; "\n"; std::cout &lt;&lt; "2**4 = " &lt;&lt; Power&lt;2,4&gt;::val &lt;&lt; "\n"; std::cout &lt;&lt; "2**5 = " &lt;&lt; Power&lt;2,5&gt;::val &lt;&lt; "\n"; std::cout &lt;&lt; "2**6 = " &lt;&lt; Power&lt;2,6&gt;::val &lt;&lt; "\n"; std::cout &lt;&lt; "2**7 = " &lt;&lt; Power&lt;2,7&gt;::val &lt;&lt; "\n"; std::cout &lt;&lt; "2**8 = " &lt;&lt; Power&lt;2,8&gt;::val &lt;&lt; "\n"; std::cout &lt;&lt; "2**9 = " &lt;&lt; Power&lt;2,9&gt;::val &lt;&lt; "\n"; std::cout &lt;&lt; "2**10 = " &lt;&lt; Power&lt;2,10&gt;::val &lt;&lt; "\n"; std::cout &lt;&lt; "2**11 = " &lt;&lt; Power&lt;2,11&gt;::val &lt;&lt; "\n"; std::cout &lt;&lt; "2**12 = " &lt;&lt; Power&lt;2,12&gt;::val &lt;&lt; "\n"; std::cout &lt;&lt; "2**30 = " &lt;&lt; Power&lt;2,30&gt;::val &lt;&lt; "\n"; std::cout &lt;&lt; "2**40 = " &lt;&lt; Power&lt;2,40&gt;::val &lt;&lt; "\n"; std::cout &lt;&lt; "2**50 = " &lt;&lt; Power&lt;2,50&gt;::val &lt;&lt; "\n"; std::cout &lt;&lt; "2**60 = " &lt;&lt; Power&lt;2,60&gt;::val &lt;&lt; "\n"; return 0; } </code></pre> <p>Disclaimer: I make no claims that this code will necessarily compile faster due to the reduction in number of template instantiations (though it might). I really only wrote it as a toy demo. I leave it as an exercise for the reader to write a version that isn't vulnerable to someone explicitly passing a value for the <code>Odd</code> parameter when using <code>Power&lt;&gt;</code>.</p>
 

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