Exercise 1: Dynamically Creating Objects
Until now, we created objects on the stack. The stack is limited in size thus when creating many objects, the stack will overflow. Also arrays created on the stack can only have a fixed size determined at compile time. To overcome these problems we have to create objects on the heap using new. In the main program, create Point objects on the heap with new using the default constructor, constructor with coordinates and the copy constructor and assign it to pointer (Point*) variables. Note that you can’t directly pass a pointer variable as argument to the copy constructor. The pointer must first be dereferenced when passing it to the copy constructor. (Point* p2=new Point(*p1)). Next call the Distance() function on the pointers and try to send the Point pointers to cout. You need to dereference the pointer when passing it as argument. Don’t forget to delete the object created with new. Test the main program. Next, we will create an array of points. First ask the user for the size of the array and read it using cin. Then try to create an array on the stack using the entered size. You will see a compiler error. Arrays on the stack must have the size set at compile time. Now create the array on the heap using new. Can you use other constructors than the default constructor for the objects created in the array? Don’t forget to delete the array after use. Don’t forget the square brackets when deleting arrays! Some C++ compilers (e.g. GCC) support variable length arrays (VLA) where the size can be determined at run-time. However this is a C99 feature that is not in the C++ standard. Because VLA is not in the C++ standard you should avoid its usage since it will lead to less portable code.

Exercise 2: Creating Array of Pointers
In this exercise we make it a little more complex. With an array of Points, all points are created with the default constructor. When creating an array of pointers, each element in the array must be created separately but can be created with other constructors than the default constructor. Thus creating an array of pointers is a two step process:
• Create an array of Point pointers with 3 elements on the heap.
• Create for each element in the array a point on the heap.
• Iterate the array and print each point in the array.
• Iterate the array again and delete each point in the array.
• Delete the array itself.
Also make a drawing of the memory layout.

Exercise 3: Creating Array Class
It is easy to forget to delete memory created with new. A good practice is to let a class manage memory. Then the client of that class does not have to manage memory and can’t forget to delete memory. So instead of creating a C array with new, you can use an array class that handle memory for you. In this exercise we are going to create an array class for Point objects (see Figure 5):
• Add a source- and header file for the Array class to your current project.
• Add a data member for a dynamic C array of Point objects (Point* m_data).
• Add a data member for the size of the array.
• Add a default constructor that allocates for example 10 elements.
• Add a constructor with a size argument. The implementation should allocate the number of elements specified by thesize input argument.
• Add a copy constructor. Keep in mind that just copying the C array pointer will create an Array object that shares the data with the original Array object. Thus you need to allocate a new C array with the same size and copy each element separately.
• Add a destructor. It should delete the internal C array. Don’t forget the square brackets.
• Add an assignment operator. Keep in mind you can’t copy only the C array pointers just as in the case of the copy constructor.
• Also don’t forget to delete the old C array and allocate new memory before copying the elements. This is because C arrays can’t grow.
Further check if the source object is not the same as the this object. If you don’t check it, then a statement like arr1=arr1 will go wrong. The internal C array will then be deleted before it is copied.
• Add a Size() function that returns the size of the array.
• Add a SetElement() function that sets an element. When the index is out of bounds, ignore the “set”. We will add better error handling later.
• Add a GetElement() function. You can return the element by reference since the returned element has a longer lifetime than the GetElement() function. When the index is out of bounds, return the first element. We will add better error handling later.
• You can also add a square bracket operator. Return a reference so the [] operator can be used for both reading and writing elements. When the index is out of bounds, return the first element. We will add better error handling later.
Point& operator [] (int index);
• In the main program, test the Array class.