Thread: Linked list problem

I don't see what the problem is, when I try to print out the list it just prints the last string entered equal to how many nodes there are. I know it's something simple, but I just can't see it.

Code:

int main(void)
{
	char yn = 'y';
	node *iter;
	node *root;

	root = new node;
	strcpy(root->customer->name, "Start");
	root->next = NULL;

	iter = root;
	while(tolower(yn) != 'n'){
		iter->next = new node;
		cout<<"Enter customer's name: ";
		cin.getline(iter->next->customer->name, 256, '\n');
		iter->next->next = NULL;
		iter = iter->next;
		cout<<iter->customer->name<<endl;
		cout<<"Enter another record? ";
		cin>>yn; cin.ignore();
	}

	iter = root;
	while(iter->next != NULL){
		cout<<iter->customer->name<<endl;
		iter = iter->next;
	}

	return 0;
}

root->customer->name would indicate that each node stores a pointer to a customer. Are you creating a new customer every time you're adding a node? Make sure that you're not overwriting the same customer everytime you create a node. You could store a customer for every node instead of a pointer if there is a known number of customers per node -

Code:

struct node
{
	struct cus
	{
		char name[256];
	}customer;
	node* next;
};

Then you'd access each name using iter->customer.name.

That worked great, but when I transferred the list to my program I get an access violation error when I run it. I went through the program step by step with the debugger and everything seems fine.

Code:

#include <iostream.h>
#include <string.h>
#include <time.h>

enum {ATLANTA = 1, NEWYORK = 2, BOSTON = 3};
enum {MASTERCARD = 1, VISA = 2, AMEX = 3};

class Customer
{
  //Everything is public until I get it to work right
  public:
	char name[256];
	int cardType;
	char cardNum[50];
	time_t active;
	int location;
	static long int acctNumber;
};

//Linked list
struct node
{
	Customer customer;
	node *next;
};

	/*Temprary prototypes*/
	void fillNode(node *newNode);
	void create_new_customer(node *iter);
	void insertNode(node *iter, node *newNode);

int main(void)
{
	char yn = 'y';
	node *iter;
	node *root;

	root = new node;
	strncpy(root->customer.name, "No Name", 255);
	root->next = NULL;

	iter = root;
	while(tolower(yn) != 'n'){
		create_new_customer(iter);
		cout<<"Enter another record? ";
		cin>>yn; cin.ignore();
		iter = root->next;
	}

	iter = root->next;
	while(iter->next != NULL){
		cout<<iter->customer.name<<endl;
		iter = iter->next;
	}
	cout<<iter->customer.name<<endl;

	//Cleanliness is godliness
	delete root, iter;

	return 0;
}

//Customer options
void create_new_customer(node *iter)
{
	node *newNode = new node;
	fillNode(newNode);

	//Find the end of the list
	while(iter->next != NULL)
		iter = iter->next;
	insertNode(iter, newNode);

	//Clean up after yourself stupid!
	delete newNode;
}

void fillNode(node *newNode)
{
  //Fill the name field
	cout<<"Enter the customer's name: ";
	cin.getline(newNode->customer.name, 256, '\n');
}

void insertNode(node *iter, node *newNode)
{
	iter->next = newNode;
	newNode->next = NULL;
	iter = newNode;
}

You're deleting things you shouldn't be, and not deleting things that you should.

You don't want to delete the node in create_new_customer(), otherwise your deleting this new customer. You shouldn't call delete on this until you're finished with it (at the end of your program).

>>//Cleanliness is godliness
>> delete root, iter;

Will only delete two nodes. You should walk through your list deleting each node.