import java.util.ArrayList;

/**
 * 
 * CMP 326 Project 5
 * 
 * <ol>
<li>A <code>Student</code> object should keep track of a first name and a last name.  These should be set by the constructor.  There should be <code>getFirst</code> and <code>getLast</code> accessor methods, but no methods to change names.</li>
<li>A <code>Student</code> object should keep track of a list of grades.  Grades are <code>double</code>.  The list should be maintained using an <code>ArrayList</code> object.  Make use of generics so that the <code>ArrayList</code> stores objects of type <code>Double</code>.</li>
<li>There should be a method called <code>addGrade</code>, with a parameter of type <code>double</code>.  The method should add that parameter to the list of grades.</li>
<li>There should be a method called <code>getAverage</code>, with no parameters.  It should return the average of grades entered so far.  Averages are not defined if no grades have been entered; in this case, return -1.</li>
<li>Every object inherits a <code>toString</code> method but the inherited one can be overridden.  Do that for <code>Student</code>.  For example, if the student is George Washington and the average is 87.5, <code>toString</code> should return the string "George Washington: average = 87.5".  But also, if the student is George Washington and no grades have been entered then <code>toString</code> should return the string "George Washington: no grades entered".</li><li><code>Student</code> should be made to implement the <code>Comparable</code> interface.  <code>Student</code> objects should be sorted by average.</li>
</ol>
 * 
 * @author Melvin Fitting
 * @version Feb 22, 2008
 *
 */

public class Student implements Comparable {
	
	private String first, last;
	private ArrayList<Double> gradeList = new ArrayList<Double>();
	
	/**
	 * 
	 * @param first Student first name
	 * @param last Student last name
	 */
	public Student(String first, String last){
		this.first = first;
		this.last = last;
	}
	
	/**
	 * 
	 * @return Student first name
	 */
	public String getFirst(){
		return first;
	}
	
	/**
	 * 
	 * @return Student last name
	 */
	public String getLast(){
		return last;
	}

	/**
	 * Adds a grade to the student's list of grades
	 * 
	 * @param grade the grade to be added
	 */
	public void addGrade(double grade){
		gradeList.add(grade);
	}
	
	/**
	 * 
	 * @return student's average, or -1 if no grades entered
	 */
	public double getAverage(){
		if (gradeList.isEmpty()) return -1;
		double sum = 0;
		for (int n = 0; n < gradeList.size(); n++)
			sum += gradeList.get(n);
		return sum/gradeList.size();
	}
	
	public String toString(){
		double average = getAverage();
		if (average < 0) return first + " " + last + " : no grades entered";
		else return first + " " + last + " : average = " + average;
	}
	
	public int compareTo(Object otherObject){
		Student other = (Student)otherObject;
		double myAverage = getAverage();
		double otherAverage = other.getAverage();
		if (myAverage < otherAverage) return -1;
		else if (myAverage > otherAverage) return +1;
		else return 0;
	}
}