[prog] C++ - linked list and segmentation fault

Robert J. Hansen rjh at sixdemonbag.org
Tue Apr 8 12:25:44 EST 2003

> I was wondering if I could get some advice on a program I am trying to
> complete for class.  It is a killer as I am new to linked lists.  I write
> the program and it compiles.  However, when it runs, it segfaults.  I'm
> sure it happens when I am creating the list.  All help would be very much
> appreciated.

Free advice: I see from the fact you're using an ifstream that you're
using C++.  C++ already has linked lists pre-made for you.  Try using
them instead.  :)

I'll post again to the list in a bit, showing you how to use the
built-in C++ list class to do what you want done.  I'll make sure to
drop lots of breadcrumbs along the way, never fear.

> #include<iostream.h> // for cin & cout


<iostream.h> is deprecated.  <iostream> should be used for all new C++

> #include<fstream.h>  // for file i/o


<fstream.h> is deprecated.  Use <fstream> instead.

>     INVENTORY_ITEM *nextItem;
>     char itemCode[7];
>     int quantity;
>     float price;
>     }; // end struct INVENTORY_ITEM


Strictly speaking, this should be called INVENTORY_NODE instead of
INVENTORY_ITEM.  Try breaking it up as follows:

	std::string itemcode;
	int quantity;
	float price;

Then, to represent a node in a linked list:

	INVENTORY_ITEM *next, *previous; // doubly-linked list

... And if you use the C++ list class, you can do away with
INVENTORY_NODE altogether.  As you'll see.  :)

Robert J. Hansen <rjh at sixdemonbag.org>

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