Question

I am not experienced in handling of the memory in a C++ program, so I would like a piece of advice in that case:

I want to create a new Object in a function in a class which is essential till the end of the program. As far as I am concerned, if I use the operator new, I should sometimes delete it. Taking into account that it must be initialized inside a class, when and how must I finally delete it?

Answer 1

Edit: Using some sort of smart pointer is often a good idea, but I believe it is still essential to have a solid understanding of manual memory management in C++.

If you want an object in a class to persist until the end of the program, you can simply make it a member variable. From what you’ve said, there’s nothing to suggest you need to use new or delete here, just make it an automatic variable. If you did want to use new and delete for practice, you should read up on constructors and destructors for a class (you can and will use new and delete outside of classes, but I’m trying to keep this relevant to your question). Here’s one I prepared earlier:

class Foo
{
    public:
        Foo();  // Default constructor.
        ~Foo(); // Destructor.

    private:
        int *member;
}

Foo::Foo() // Default constructor definition.
{
    member = new int; // Creating a new int on the heap.
}

Foo::~Foo() // Destructor.
{
    delete member; // Free up the memory that was allocated in the constructor.
}

This is a simple example, but it will hopefully help you out. Note that the variable will only persist as long as the object is alive. If the object is destroyed or goes out of scope, the destructor will be called and the memory will be freed.