For use with CMSC-341, Spring 99,  Project 2

Here is the definition of the main function

Copy it to your Proj2.C file. 

Remember:
 -- complete the documentation
 -- write the function
       void getCommandLine(int argc, char * argv[], 
                           int * nelem, int * startval,
	                   List<T> ** lst)
------------------------------------------------


// Reads command line arguments and inserts values
// into nelem, startval, and lst appropriately.
//
// The command line must be of the form:
//      Proj2 number-of-entries start-val list-type
// where:
//   number-of-entries is the number of integers to 
// insert into the list,
//   start-val is the first integer to be inserted, and
// list-type is either LinkedList or ArrayList
//
// This function constructs the appropriate type
// of list (LinkedList or ArrayList) based on the last
// command line argument.
// 
// Param: argc - the number of command line arguments
// Param: argv - array of the command line arguments
// Param: nelem - upon return will contain the number of 
// elements to be inserted in list
// Param: startval - upon return will contain the 
// starting value for the elements
// Param: lst -- upon return will contain a pointer to the 
// List on which to perform the operations.  The List itself
// will be constructed in this function.
//
// This function must exit (after issuing a "Usage" message to
// cerr) if any command line arguments are invalid:
//  1) the number of arguments must be correct
//  2) number-of-entries must be greater than zero
//  3) start-value must be a number
//  4) list-type must be either "LinkedList" or "ArrayList"
template <class T>
void getCommandLine(int argc, char * argv[], 
		    int * nelem, int * startval,
		    List<T> ** lst);

int main(int argc, char *argv[])
{
  int i;
  int nelem;     // number of elements
  int startval;  // starting value for elements
  Iterator<int> * iter1;
  Iterator<int> * iter2;
  List<int> * list;

  getCommandLine(argc, argv, &nelem, &startval, &list);

  cout << "------- Using " << list->ToString() << " -------" << endl << endl;

  // Insert elements at index 1 into initially empty list.
  cout << "-- Insert (at index 1) " << nelem << " elements, "; 
  cout << "starting with " << startval << " --" << endl;
  for (i = 1; i <= nelem; i++)
    {
      int val = startval + i - 1;
      list->Insert(val, 1);
    }
  cout << *list << endl;
  cout << "length = " << list->Length() << endl;

  // Clear the list
  cout << "-- Clear the list --" << endl;
  //  for (i = 0; i < nelem; i++)
  //    list->Delete(1);
  list->MakeEmpty();
  cout << *list << endl;
  cout << "length = " << list->Length() << endl;

  // Insert elements in-order into initially empty list.
  cout << "-- Insert (in-order) " << nelem << " elements, "; 
  cout << "starting with " << startval << " --" << endl;
  for (i = 1; i <= nelem; i++)
    {
      int val = startval + i - 1;
      list->Insert(val, i);
    }
  cout << *list << endl;
  cout << "length = " << list->Length() << endl;


  // Clear the list
  cout << "-- Clear the list --" << endl;
  for (i = 0; i < nelem; i++)
    list->Delete(1);
  cout << *list << endl;
  cout << "length = " << list->Length() << endl;

  // Append elements into initially empty list.
  cout << "-- Append " << nelem << " elements, "; 
  cout << "starting with " << startval << " --" << endl;
  for (i = startval; i < startval + nelem; i++)
    list->Append(i);
  cout << *list << endl;
  cout << "length = " << list->Length() << endl;
  
  // show that more than one iterator can be used 
  // at one time
  cout << "-- Use multiple iterators simultaneously --" << endl;
  iter1 = list->GetIterator();
  iter2 = list->GetReverseIterator();
  while (iter1->HasNext())
    cout << (iter1->Next() + iter2->Next()) << " ";
  cout << endl;

  // de-allocate iter2, don't need it anymore  
  delete iter2;  iter2 = NULL; 
  
  // show that iterator can be output directly
  cout << "-- Output directly from reverse iterator --" << endl;
  delete iter1;  // de-allocate old iter1
  iter1 = list->GetReverseIterator();
  cout << iter1  << endl;
  
  // de-allocate iter1, don't need it anymore  
  delete iter1;  iter1 = NULL; 

  // repeatedly delete first element, even on an empty list
  cout << "Repeatedly delete 1st element, even on empty list" << endl;
  for (i = 0; i < nelem + 1; i++)
    {
      cout << *list << endl;
      list->Delete(1);
    }
  cout << *list << endl;

}