qsort on a std::vector<float*> _data
<p>I need help on a sort program for <code>std::vector&lt;float*&gt; _data</code>.
The sort criteria can be selected on index i1, i2, i3... of the _data in a ascend manner. The i1 is a 
 <code>float *i1_data = _data[i1];</code></p>

<p>How do I accomplish it?</p>
