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POShadowed Variable Issue Qt
 

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    <p>I'm running into a problem with a break being thrown in my Qt5 application, when I'm trying to implement a DBSCAN.</p> <p>So I cracked open the debugger to try to figure out what might be causing the issue, and it says I have two copies of the same variable in scope, one called <code>index</code> and another called <code>index &lt;shadowed 1&gt;</code>. I don't understand how I could have another copy of the <code>index</code> variable in scope? They both hold 2 different values, and the one that doesn't have the <code>&lt;shadowed 1&gt;</code> part in it has members that point to memory access error locations, so I assume this is the one being used.</p> <pre><code>QMap&lt;int, Point*&gt; kDistPlot; for (int i = 0; i &lt; points-&gt;size(); i++) { Point *point = points-&gt;at(i); QMap&lt;int, Point*&gt; pointDistanceList; for (int j = 0; j &lt; points-&gt;size(); j++) { if (i == j) continue; Point *distPoint = points-&gt;at(j); int dist = distance(point, distPoint); Q_ASSERT_X(dist &gt;= 0, __FUNCTION__, "Distance can't be negative..."); pointDistanceList.insert(dist, distPoint); } QMap&lt;int, Point*&gt;::const_iterator index = pointDistanceList.begin(); index += k - 1; Point* kPoint = (*index); //this is where the error is int kDist = index.key(); kDistPlot.insert(kDist, kPoint); } </code></pre> <p>It triggers this exception, inside the QMap class:</p> <pre><code> Stopped in thread 1 by: Exception at 0x581c79e8, code: 0xc0000005: read access violation at: 0x0, flags=0x0(first chance) </code></pre> <p>Can anyone explain this? I'm thoroughly confused.</p>
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    1. USK. Barresi
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    1. CODo you have any other variables named index? Like member variables? (I'm assuming this code is in a class method)
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    2. CONope, no member variables are named index.
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      1. USK. Barresi
    3. CO`QMap<int, Point*>::const_iterator index = pointDistanceList.begin();` is the only defined `index` which I see.
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      1. POShadowed Variable Issue Qt
      1. USMark Garcia
 

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