I need some help

**OH_HRVAT** · 05-31-2005

OK...i dont know if its too early at work, or what...but i shouldnt be having problems reading in some data and storing them into linked lists...does anyone see any errors with this code?

Code:

#include <stdio.h>
#include <stdlib.h>
#include <iostream.h>
#include <fstream.h>

class int_node
{
	public:
		long item_num;
		int_node *next;
};

class text_node
{
	public:
		char descr[150];
		text_node *next;
};

int main()
{
	FILE *masterIntIn;
	masterIntIn = fopen("C:\\Cplusplus\\dm\\bin\\master_int.txt" , "r");

	FILE *itemLocateNumIn;
	itemLocateNumIn = fopen("C:\\Cplusplus\\dm\\bin\\item_location_num.txt" , "r");

	FILE *matchItemsOut;
	matchItemsOut = fopen("C:\\Cplusplus\\dm\\bin\\matching.txt" , "w");

	FILE *itemLocateDescrIn;
	itemLocateDescrIn = fopen("C:\\Cplusplus\\dm\\bin\\item_location_descr.txt" , "r");

	int_node *current_master;
	int_node *root_master;
	root_master = new int_node;
	root_master->next = NULL;
	current_master = root_master;

	int_node *current_lnum;
	int_node *root_lnum;
	root_lnum = new int_node;
	root_lnum->next = NULL;
	current_lnum = root_lnum;

	text_node *current_descr;
	text_node *root_descr;
	root_descr = new text_node;
	root_descr->next = NULL;
	current_descr = root_descr;

	while ( !feof( itemLocateDescrIn ) )
	{
		char tempCh[150];
		fgets( tempCh , itemLocateDescrIn , 150 );
		strcpy( current_descr->descr , tempCh );
	
		current_descr->next = new Text_node;
		current_descr = current_descr->next;
		current_descr->next = NULL;
	}	

	while ( !feof( masterIntIn ) )
	{
		long tempLong;
		fscanf( masterIntIn , "%ld" , &tempLong ); 
		strcpy( current_master->item_num , tempLong );
	
		current_master->next = new Int_node;
		current_master = current_master->next;
		current_master->next = NULL;
	}

	while ( !feof( itemLocateNumIn ) )
	{
		long tempLong;
		fscanf( itemLocateNumIn , "%ld" , &tempLong ); 
		strcpy( current_lnum->item_num , tempLong );
	
		current_lnum->next = new Int_node;
		current_lnum = current_lnum->next;
		current_lnum->next = NULL;
	}	

	current_descr = root_descr;
	current_master = root_master;
	current_lnum = root_lnum;

	while ( current_master->next != NULL )
	{
		printf("%l \n" , current_master->item_num);
		current_master = current_master->next;
	}

	return 0;
}

thanks

~omega

**Salem** · 05-31-2005

Is this the problem of outputting the last record twice, or some other problem?

> while ( !feof( itemLocateNumIn ) )
Why you shouldn't do this is in the FAQ

**hk_mp5kpdw** · 05-31-2005

Since this is the C++ board, I would say you should try to stick with the C++ headers and C++ stream I/O; drop the FILE*, fopens and printfs in favor of ofstream/ifstream and cout. You can also simplify things greatly by switching to a STL container instead of your linked list.

One error you have is this:

Code:

while ( !feof( masterIntIn ) )
{
    long tempLong;
    fscanf( masterIntIn , "%ld" , &tempLong ); 
    strcpy( current_master->item_num , tempLong );
	
    current_master->next = new Int_node;
    current_master = current_master->next;
    current_master->next = NULL;
}

while ( !feof( itemLocateNumIn ) )
{
    long tempLong;
    fscanf( itemLocateNumIn , "%ld" , &tempLong ); 
    strcpy( current_lnum->item_num , tempLong );
	
    current_lnum->next = new Int_node;
    current_lnum = current_lnum->next;
    current_lnum->next = NULL;
}

You do not use strcpy to copy a long value into another long value. A simple assignment (=) should be all you need.

Try to use C++ to your advantage. If you follow my suggestion of using an STL container, the code to process the master_int file (for example) could be replaced with:

Code:

ifstream masterIntIn("C:\\Cplusplus\\dm\\bin\\master_int.txt");
list<long> longList;  // Linked-list object to store values into

// Make sure file was opened
if( !masterIntIn.is_open() )
{
    cerr << "Error, could not open master_int.txt file." << endl;
    exit(1);
}

// Read all values from "masterIntIn" file and store into "longList" linked-list object
copy(istream_iterator<long>(masterIntIn),istream_iterator<long>(),back_inserter(longList));

You would need to include <list>, <algorithm>, and possibly <iterator> to get the above code to work.

Thread: I need some help

Thread Tools

Search Thread

Display

I need some help