Thread: Assignment Operator Access Violation

I've looked around a bit on Google and at a few different articles but I'm pretty sure I'm not looking for the right information.

In the following scenario, I have a very basic assignment operator:

Code:

class MyClass
{
public:
	MyClass(Bar *bar) : myBar(bar) {};
	MyClass(): myBar(NULL) {};
	MyClass& operator=(const MyClass &rhs)
	Bar *myBar;
};

MyClass& MyClass::operator=(const MyClass &rhs)
{
	myBar= rhs.myBar;  // explodes here, access violation at 0x00000000
}

int main()
{
	Bar *someBar = new Bar();

	MyClass *myClass = new MyClass(someBar);
	MyClass *myClass2 = new MyClass();

	*myClass2 = *myClass;

	return 0;
}

As a note, myBar is an object that is constructed outside of MyClass and is

What I expect is that the address of rhs.myBar be assigned to myBar. However, I get an access violation attempting to write to memory 0x00000000 which tells me that I'm trying to write into a null pointer.

My first thought was that I should be asking for the address of rhs.myBar like this:

Code:

myBar = &rhs.myBar;

But that only results in the error message "cannot convert from Bar *const *' to Bar*'". I'm pretty sure const casting is not applicable here and I'm pretty sure that my first thought is just plain wrong.

Obviously my code is incorrect. What am I doing wrong here? Where can I find more information about the particular type of operation I'm trying to do?

I doubt the error is in that code (you are not dereferencing the pointer anywhere). You shouldn't even need to define the assignment operator yourself.

Aside from missing ; and missing return statement (and the missing delete statements!), the code compiles and runs fine.
If you encounter a problem, you would have to post the smallest possible amount of code that demonstrates the problem.