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POshould I use the algorithm or hand-code it in this case?
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  1. POshould I use the algorithm or hand-code it in this case?
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    copied!<p>Ok, someone tell me which would be better. I need to |= the elements of one vector with another. That is, I want to</p> <pre><code>void orTogether(vector&lt;char&gt;&amp; v1, const vector&lt;char&gt;&amp; v2) { typedef vector&lt;char&gt;::iterator iter; for (iter i = v1.begin(), iter j = v2.begin() ; i != v1.end(); ++i, ++j) *i |= *j; } </code></pre> <p>I can't use for_each due to needing to process 2 collections. I suppose I could do something like</p> <pre><code>struct BitWiseOr { char operator()(const char&amp; a, const char&amp; b) {return a | b;} }; void orTogether2(vector&lt;char&gt;&amp; v1, const vector&lt;char&gt;&amp; v2) { transform(v1.begin(), v1.end(), v2.begin(), v1.begin(), BitwiseOr()); } </code></pre> <p>Is this a more efficient solution even though the top one is in place, but the bottom is an assign? This is right in the middle of a processing loop and I need the fastest code possible.</p> <p>Edit: Added (obvious?) code for BitwiseOr. Also, I'm getting a lot of comments on non-related things like checking the lengths of v2 and changing the names. This is just an example, the real code is more complicated.</p> <p><strong>Well, I profiled both. orTogether2 is much faster than orTogether, so I'll be going with the transform method.</strong> I was surprised, orTogether2 was about 4 times faster in MSVC9 release mode. I ran it twice, changing the order the second time to make sure it wasn't some sort of cache issue, but same results. Thanks for the help everyone.</p>
 

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