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    <p>Your parameterised constructor of <code>Shape</code> does this:</p> <pre><code>vertexArray = vertices; </code></pre> <p>Where <code>vertices</code> is a function parameter declared as <code>double vertices[]</code>. This is syntactic sugar to <code>double *vertices</code>, i.e., you're copying a <em>pointer</em> (because arrays decay to pointers when passed to functions).</p> <p><code>vertexArray</code> is defined as a pointer inside the class. You even mention it's a "dynamic array," but then you initialise it with an array allocated on the stack (a local variable inside <code>display()</code>). This makes the pointer dangling.</p> <p>You will have to make <code>vertexArray</code> an array and copy the data, not just the pointer. Something like this:</p> <pre><code>class Shape { // ... double vertexArray[4]; // ... }; Shape::Shape(int shapeType, double vertices[], int color[]) { type = shapeType; if (shapeType==0) //shape is a rectangle { numVertices = 4; } else if(shapeType==1) //shape is a circle { //shape is a circle, therefore the second array param is in fact an array of size 2 containing the (x, y)-coordinates of the circle origin... center = vertices; } else if (shapeType==2) //shape is a triangle { numVertices = 3; } if (shapeType!=1) //as long as shape is NOT a circle, interpret the second constructor parameter as a list of vertices { std::copy(vertices, vertices + numVertices, vertexArray); } } </code></pre> <p>And analogically for <code>color</code> as well, of course.</p> <p><strong>Extra suggestions</strong></p> <p>Of course, this code would be much better using <code>std::vector</code> or something similar instead of plain arrays, using and <code>enum</code> instead of <code>int</code> for <code>shapeType</code> etc. I suggest you pick up a <a href="https://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list">good C++ book</a>.</p>
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    1. COThank you so much for the detailed feedback! I'm off to class but will look at this in detail within the hour.
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    2. COYou have helped SO MUCH! In addition to opening my eyes in the direction of my (now obviously foolish) mistake, you showed me a fantastic STL copy algorithm for future use.
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