/** Linked list II - Adding at the end of the list */

   // ~cps330/Examples/list_II.C 

#include <stream.h>
#include <String.h>

class data_line {
  public:
    String string;
    data_line *next;
  };

main() {
  String input_string;       // Used to store string
  data_line *top;            // Will point to the top element
  data_line *tail;           // Will point to the last element
  data_line *ptr;            // Will point to the currnet element

  top = NULL;    // Indicate that the list is empty
  tail = NULL;   // Indicate that there is no end element

  while(1) { // Prompt for lines
    cout << "Enter a string \n";
    readline(cin,input_string);
    if ( cin.eof() ) break;

    ptr = new data_line;  // Allocate an object
    cout << "Allocated a new string at " << form("%x",ptr) << "\n";

    ptr->string = input_string;    // Copy string into new space

    ptr->next = NULL;  // Will always be at the end of the list
    if ( top == NULL ) {
       cout << "Adding the first element\n";
       top = ptr;
    } else {
       cout << "Adding line after element " << form("%x",tail) << "\n";
       tail->next = ptr;  // Add at the end 
    }
    tail = ptr;  // The entry just added is the new last entry
  }

  cout << " ---------------  Print the list ------------------\n";
  cout << "Top: " << form("%x",top);
  cout << "  Tail: " << form("%x",tail) << "\n";

  ptr = top; 
  while ( ptr != NULL ) {
    cout<<"Address:"<<form("%x",ptr)<<" ->next "<<form("%x",ptr->next);
    cout<<" String:" << ptr->string << "\n";
    ptr = ptr->next;
  }
}