// LinkedListData - store name data in
//                  a linked list of objects
#include <stdio.h> 
#include <iostream.h>
#include <string.h>

// NameDataSet - stores name and social security
//               information
class NameDataSet
{
    public:
        char szFirstName[128];
        char szLastName [128];
        int  nSocialSecurity;

        // the link to the next entry in the list
        NameDataSet* pNext;
};

// the pointer to the first entry
// in the list
NameDataSet* pHead = 0;

// addTail - add a new member to the linked list
void addTail(NameDataSet* pNDS)
{
    // make sure that our list pointer is NULL
    // since we are now the last element in the list
    pNDS->pNext = 0;

    // if the list is empty,
    // then just point the head pointer to the
    // current entry and quit
    if (pHead == 0)
    {
        pHead = pNDS;
        return;
    }

    // otherwise find the last element in the list
    NameDataSet* pCurrent = pHead;
    while(pCurrent->pNext)
    {
        pCurrent = pCurrent->pNext;
    }

    // now add the current entry onto the end of that
    pCurrent->pNext = pNDS;
}

// getData - read a name and social security
//           number; return null if no more to
//           read
NameDataSet* getData()
{
    // get a new entry to fill
    NameDataSet* pNDS = new NameDataSet;

    // read the first name
    cout << "\nEnter first name:";
    cin  >> pNDS->szFirstName;

    // if the name entered is 'exit'...
    if ((strcmp(pNDS->szFirstName, "exit") == 0)
        ||
        (strcmp(pNDS->szFirstName, "EXIT") == 0))
    {
        // ...delete the still empty object...
        delete pNDS;

        // ...return a null to terminate input
        return 0;
    }

    // read the remaining members
    cout << "Enter last name:";
    cin  >> pNDS->szLastName;

    cout << "Enter social security number:";
    cin  >> pNDS->nSocialSecurity;

    // zero the pointer to the next entry
    pNDS->pNext = 0;

    // return the address of the object created
    return pNDS;
}

// displayData - output the index'th data set
void displayData(NameDataSet* pNDS)
{
    cout << pNDS->szFirstName
         << " "
         << pNDS->szLastName
         << "/"
         << pNDS->nSocialSecurity
         << "\n";
}

int main(int nArg, char* pszArgs[])
{
    cout << "Read name/social security information\n"
         << "Enter 'exit' for first name to exit\n";

    // create (another) NameDataSet object
    NameDataSet* pNDS;
    while (pNDS = getData())
    {
        // add it onto the end of the list of
        // NameDataSet objects
        addTail(pNDS);
    }

    // to display the objects, iterate through the 
    // list (stop when the next address is NULL)
    cout << "Entries:\n";
    pNDS = pHead;
    while(pNDS)
    {
        // display current entry
        displayData(pNDS);

        // get the next entry
        pNDS = pNDS->pNext;
    }
    return 0;
}