Extra Node with Link List

[sharkbait]

I'm developing a program that stores information about different companies in a link list. I must read the information in from a text file, and store it into a link list. I have an extra node that is appearing at the end of my data. I'm unsure if it is from reading it in or how I am displaying it. Here is my code:


At the end the empty strings and default value for ints. I'm unsure where I'm getting this issue or how it's occurring.

[kbw]

It's happening during the read. The file doesn't know it's reached the end until a failed read occurs. So it passes the "while (!eof)" test, then fails on the getline call, but you don't really test it there.

[Duthomhas]

Line 11: you are looping on EOF, but you need to test for EOF after attempting to read data, not before. You create a new (empty) node before attempting to read potentially non-existing data. Don't do that.

void company::read_in(istream& filein)
{               
                NodePointer crt;
                assert( head == NULL );
                while (true)
                {
                                // This is our temporary input node
                                Node n;
                                filein >> ws;  // skip whitespace

                                // this is where we will ATTEMPT to get data
                                getline(filein, n.company);
                                getline(filein, n.phonenumber);
                                filein >> n.avg_salary;
                                filein >> n.mngr_salary;

                                // Now, ONLY if we succeeded, add a copy of the node to the list
                                if (!filein) break;

                                // You do have a copy ctr, right? We use it here as:
                                //   foo = new Node( n );
                                if (head == NULL)
                                                head = crt = new Node( n );
                                else
                                                crt->link = new Node( n );
                }

                // Frankly, the Node ctr should have done this for you already:
                if (head != NULL)
                                crt->link = NULL;
}

You have named your nodes variously "person" and "node" -- I named it "Node". Substitute the proper name. Make sure that your constructor properly initializes the fields of a Node:

Node::Node(
  const string& company = "",
  const string& phonenumber = "",
  double avg_salary = 0.0,
  double mngr_salary = 0.0,
  Node* link = NULL  // <-- this is IMPORTANT
  ):
  company( company ),
  phonenumber( phonenumber ),
  avg_salary( avg_salary ),
  mngr_salary( mngr_salary ),
  link( link )  // <-- this is IMPORTANT
  {
  }

Also, don't forget a copy constructor:

Node::Node( const Node& n )
{
  company = n.company;
  phonenumber = n.phonenumber;
  avg_salary = avg_salary;
  mngr_salary = mngr_salary;
  link = n.link;
}

Hope this helps.

[sharkbait]

Ohhhhh that makes a lot of sense. Thank you very much.