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POWhen should one be careful using a bitset in place of a bool array?
 

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  1. POWhen should one be careful using a bitset in place of a bool array?
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    <p>I'm working on a mobile phone application and I see a potential opportunity for performance improvement. Throughout the code I use bool arrays to keep track of which objects are active. For example I'd check to see if the ith MyObject is active by doing the following:</p> <pre><code>if(activeMyObjects[i]){ // it's active so do something... } </code></pre> <p>Since the max number of my objects is in the range [5,20] I think I can replace the activeMyObjects bool array with a bitset in the form of a single integer "activeMyObjects". Then I can do the following:</p> <pre><code>// check if ith object is active if(activeMyObjects &amp; (1 &lt;&lt; i)){ // it's active... } // activate the ith object activeMyObjects |= (1 &lt;&lt; i); // reset all myObjects to inactive activeMyObjects = 0; // and so on... </code></pre> <p><strong>Is there anytime when switching to the bitset could actually degrade performance?</strong> The language I'm using is c. Also note this code is called very often (frequency in the range 30 - 60 Hz).</p> <p><strong>Edit:</strong> Another piece of information: the bitsets have another advantage in that I can easily tell if any of the objects are active at all. so I can skip a loop where I check each item to see if it's active by first checking if(activeMyObjects). when I use the array this is trickier... my approach was to have an additional counter int which is incremented whenever a MyObject is actived and decremented whenever a MyObject is deactivated... this way I would just check if(activeMyObjectsCount > 0) before the loop where I check each one.</p>
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