/** A class that will make use of another class.
 **/
public class CSClass {

  public static void main(String[] args) {
    if (args.length == 0) {
      System.out.println("usage java CSClass [student names]");
    }
    else {
      int numberOfStudents = args.length;
      CSClass cs161 = new CSClass( numberOfStudents );
      cs161.enroll( args );
      cs161.assignLabPartners();
      cs161.listRoster();
    }
  }

  // Instance fields
  CSStudent students[] = null;
  int last = 0;

  public CSClass( int number ) {
    students = new CSStudent[ number ];
  }

  public void enroll(String[] names) {
    int numberOfStudents = names.length;
    int id = 0;
    
    for (int arg = 0; arg < numberOfStudents; arg++) {

      String name = names[arg];

      id++;                             // assign next id
      String idString = String.valueOf(id); // as a String

      CSStudent aStudent = new CSStudent( name, idString);

      aStudent.setGrade(100);
    
      // save the reference to the current student in the next array slot
      students[last] = aStudent;
      last++;
    }
  }

  public void assignLabPartners() {

    // Assign every other pair of students as lab partners
    int next = 0;
    int pairs = last / 2;
    while (pairs > 0) {
        students[next].setLabPartner( students[next+1] );
        students[next+1].setLabPartner( students[next] );
        next += 2;
        pairs--;
    }

    // If there were an odd number of students in the array the
    // last one won't have a lab partner.
  }

  public void listRoster() {
    for (int i = last - 1; i >= 0; i--) {
      //  Ask each Student to identify itself, last to first
      System.out.println(students[i]);
    }
  }
}