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list ADTs

tom eustace
Greenhorn

Joined: Feb 01, 2004
Posts: 2
hi all,
been having a problem which for the life of me i can't figure out. The assignment requires the use of a doubly linked list ADT, but i keep getting a NullPointerException which i don't understand, chances are its something silly which i'm just not seeing well at least i hope it is. Heres what i've got, i've tracked the bug to the insertAfterCurrent() method, there are other methods that might have problems aswell and some that are downright silly, but one step at a time.

thanks for any help
later
y'all.
Jeff Langr
author
Ranch Hand

Joined: May 14, 2003
Posts: 762
You should post a short piece of client (testing) code that demonstrates the problem.
-Jeff-


Books: Agile Java, Modern C++ Programming with TDD, Essential Java Style, Agile in a Flash. Contributor, Clean Code.
tom eustace
Greenhorn

Joined: Feb 01, 2004
Posts: 2
ok, i should have done so before. so here is some test code that throws the NullPointerException.

For my assignment i need to be able to create possible many lists and manipulate them. Hence this line which i think is where the problem starts
but the debugger points to the insertAfterCurrent() method and the second.setPrev(after_current); line specifically.
once again thanks for any halp
t
Jeff Langr
author
Ranch Hand

Joined: May 14, 2003
Posts: 762
I think in your test you don't want to advance after an insertion:

And offEnd seems like it should be:

-Jeff-
 
I agree. Here's the link: http://aspose.com/file-tools
 
subject: list ADTs