hello I have a opengl canvas class, which contains a vector that holds a list of shape objects that gets displayed. Anyways the problem is when I try to remove the shape I get an access violation void GLcanvas::addShape(GLshape* x) { theDisplayLists.push_back(x); //will be used to remove object theDisplayLists[numInList]->position = theDisplayLists.begin(); numInList++; } //where x will be (shape class)->position void GLcanvas::removeShape(GLshape** x) { theDisplayLists.erase(x); //access violation numInList--; } I'm using borland builder 6

Not sure if you noticed it but you added a pointer to the shape to the list and you're trying to remove a "pointer to a pointer" from the list... That's whats causing your access violation.

Ok, first off, and this doesn't have anything to do with your problem, the numInList variable is pointless, since std::vector give a size() member function that will tell you how many elements are in the vector.

As for your actual problem, you're probably supplying an invalid value for your element address that isn't in the actual vector. Consider instead using the value of the GLshape pointer and using the remove-erase idiom to remove the item. Ex:

void GLcanvas::removeShape(GLshape* x){  theDisplayLists.erase(std::remove(theDisplayLists.begin(), theDisplayLists.end(), x),                        theDisplayLists.end());}