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Re: null vs undefined

 
 
Victor Bazarov
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      08-19-2003
"Web Developer" <(E-Mail Removed)> wrote...
> Whats the difference from null and undefined in C++ as opposed to Java.


What's "undefined" in your sentence? 'null' has only one meaning
in C++ -- it's part of the concept of "null pointer value". That
concept defines a value of a pointer that [in C++ virtual machine]
doesn't represent any object (or function). 'Undefined' is just
that, has no particular definition (whether it's about a value or
behaviour). If you are asking specifically about pointers, then
pointers have undefined values when they are uninitialised. They
have "null pointer value" when you initialise them to be that:

sometype *pointer = 0;

(conversion from an integral expression that evaluates to (int)0
to a pointer to object yields the "null pointer value").

Victor


 
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