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  1. PO
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    <p>I think the algorithm you're looking for could be '<a href="http://en.wikipedia.org/wiki/Nth_root_algorithm" rel="nofollow">nth root</a>'. With an initial guess of 1 (for k == 0):</p> <pre><code>#include &lt;iostream&gt; using namespace std; float pow(float base, float ex); float nth_root(float A, int n) { const int K = 6; float x[K] = {1}; for (int k = 0; k &lt; K - 1; k++) x[k + 1] = (1.0 / n) * ((n - 1) * x[k] + A / pow(x[k], n - 1)); return x[K-1]; } float pow(float base, float ex){ if (base == 0) return 0; // power of 0 if (ex == 0){ return 1; // negative exponenet }else if( ex &lt; 0){ return 1 / pow(base, -ex); // fractional exponent }else if (ex &gt; 0 &amp;&amp; ex &lt; 1){ return nth_root(base, 1/ex); }else if ((int)ex % 2 == 0){ float half_pow = pow(base, ex/2); return half_pow * half_pow; //integer exponenet }else{ return base * pow(base, ex - 1); } } int main_pow(int, char **){ for (int ii = 0; ii&lt; 10; ii++){\ cout &lt;&lt; "pow(" &lt;&lt; ii &lt;&lt; ", .5) = " &lt;&lt; pow(ii, .5) &lt;&lt; endl; cout &lt;&lt; "pow(" &lt;&lt; ii &lt;&lt; ", 2) = " &lt;&lt; pow(ii, 2) &lt;&lt; endl; cout &lt;&lt; "pow(" &lt;&lt; ii &lt;&lt; ", 3) = " &lt;&lt; pow(ii, 3) &lt;&lt; endl; } return 0; } </code></pre> <p>test:</p> <pre><code>pow(0, .5) = 0.03125 pow(0, 2) = 0 pow(0, 3) = 0 pow(1, .5) = 1 pow(1, 2) = 1 pow(1, 3) = 1 pow(2, .5) = 1.41421 pow(2, 2) = 4 pow(2, 3) = 8 pow(3, .5) = 1.73205 pow(3, 2) = 9 pow(3, 3) = 27 pow(4, .5) = 2 pow(4, 2) = 16 pow(4, 3) = 64 pow(5, .5) = 2.23607 pow(5, 2) = 25 pow(5, 3) = 125 pow(6, .5) = 2.44949 pow(6, 2) = 36 pow(6, 3) = 216 pow(7, .5) = 2.64575 pow(7, 2) = 49 pow(7, 3) = 343 pow(8, .5) = 2.82843 pow(8, 2) = 64 pow(8, 3) = 512 pow(9, .5) = 3 pow(9, 2) = 81 pow(9, 3) = 729 </code></pre>
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    1. POself made pow() c++
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    1. USCapelliC
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      1. VTUpMod
    1. COsorry had other projects to work on. this crashes when given say a `.3`
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      1. USgardian06
    2. COI tried adding .3, seems to work (I'm using GCC 4.5). but see the edit for the *base* == 0...
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    3. COI tried adding 1/3 exponent, values are garbled, I'm going to test more...
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