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    <p>Your new RoadLine class will certainly lead to disaster :</p> <pre><code>RoadLine::RoadLine(CvPoint* aLine, int aLane){ line = aLine; lane = aLane; } RoadLine::RoadLine(const RoadLine &amp; myRoadLine){ line = myRoadLine.line; lane = 1; } RoadLine::~RoadLine(){ delete line; } </code></pre> <p>code using it :</p> <pre><code> if(lineCount == a){ cvLine(img_final, roadLine[0], roadLine[1], CV_RGB(0,0,255), 3, CV_AA, 0 ); RoadLine myLine = RoadLine(roadLine, 1);//create object on the Stack roadVector-&gt;push_back(myLine); //Push COPY of myLine cvShowImage("Plate Detection", img_final); cvWaitKey(0); }//Stack-based object "myLine" is automatically destroyed here (leaves scope) </code></pre> <p>the automatic destruction of "myLine" will delete "myLine.line" (in RoadLine's dtor) but "myLine.line" is still referenced in the vector (you just pushed it).</p> <p>You have to either make a DEEP COPY of line (as others suggested), something like this :</p> <pre><code>RoadLine::RoadLine(const RoadLine &amp; myRoadLine){ line = new CvPoint(*myRoadLine.line);//assuming CvPoint can be copy-constructed lane = 1; } </code></pre> <p>Or use a CvLine object rather than a pointer (or something else, need more context)</p> <p>EDIT : Dirk Gently's copy-ctorhas a bug, because it leaks memory to the former "line"-member should be :</p> <pre><code>RoadLine&amp; operator=(const RoadLine &amp; o){ if (this != &amp;o) { //Remember to check for self-assignment. delete []line;//delete[] vs. delete ! line = 0;//if next line throws at least we won't double-delete line line = new CvPoint[ 2 ]; //this might throw ! should catch (or redesign to get rid of new (prefered) line[ 0 ] = o.line[ 0 ]; line[ 1 ] = o.line[ 1 ]; lane = o.lane; } return *this; } //consistent constructor ! RoadLine::RoadLine(CvPoint* aLine, int aLane) :line(new CvPoint[2]),//might throw, but its better to throw in initializer ! (if you just have one pointer it might be ok to do it like this) lane(aLane) { line[0] = aLine[0]; line[1] = aLine[1]; } RoadLine::~RoadLine(){ delete[] line;//also use delete[] vs. normal delete here ! } </code></pre> <p>EDIT 2 : I almost forgot that I had an idea why it crashes ! maybe you try to build a pair with last and last+1 CvPoint (like this obviously false code)?</p> <pre><code>CvPoint Pnts[2] = {CvPoint(0,0),CvPoint(1,1)}; Roadline Line(&amp;Pnts[1],1);//tries to access Pnts[2] which is one past end ! </code></pre>
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    1. POVector of pointers problem
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    1. COHi qwerty, Thanks for your help. I have a quick question regarding your answer. Are you saying that I only need to change the copy const? or do i need to change how the code is implemented? Also in the copy cont line is of type CvPoint* so should that line read something like:
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    2. COline = new CvPoint*(*myRoadLine.line);
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    3. COsorry i now see how line = new CvPoint(*myRoadLine.line);is correct. however i am still unsure about how it is used. thanks again
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