Programming

Now you've turned it from invalid syntax, into something that's likely to crash... Think about what you're doing: You're trying to assign the contents of an unassigned pointer to NULL -- in other words, picking some random, arbitrary bit of memory and trying to write 0 into it.

Fortunately, this is a compiler error anyway since 0 isn't a ClassA.

How about:

Code:

classA *point=NULL;

NULL is like zero, but is of type void, which C++ won't complain about.

Allright, my C++ knowledge are definitively rusty... But I believe, there is a slight inaccuracy in the statements claimed.

Code:

ClassA *point;
point = 0;
point = new ClassA;

What let you believe this? Using 0 for NULL is perfectly legal in C++, there are actually equal. Stroustrup himself prefers to use "0": Should I use NULL or 0

This line may also work:

Code:

point = new ClassA;

as long as the ClassA provides a default constructor.

Cheers, Loïc

Even though any other integer isn't. Hooray, more weird special cases to learn in the C++ language

Naturally he'd prefer to use 0, and so not need to include stdio.h, but it's a strange inconsistency for the C++ language to let you assign 0 when it refuses to let you assign any other integer pointer value. That's what the void type used to be for, which is what NULL was of..

As you mentioned already, C++ is a strongly typed language (or a least claims to be so).
If you try the following assignment:

Code:

ClassA* point = ((void*) 0); // ((void*)0) is the C definition for NULL

Then the compiler shall complain that you're trying to perform an invalid conversion from void* to ClassA* ...

Loïc