using System;

using System.Collections.Generic;

​

public struct Record

{

    public string course;

    public string grade;

    public Record(string course, string grade)

    {

        this.course = course;

        if (grade == "A")

            this.grade = "4.0".ToString();

        else if (grade == "B")

            this.grade = "3.3".ToString();

        else if (grade == "C")

            this.grade = "2.7".ToString();

        else

            this.grade = "0.0".ToString();

    }

}

​

public class StudentRecord : IComparable<StudentRecord>

{

    private string name;

    private double GPA;

    public double gpa

    {

        get

        {

            return GPA;

        }

    }

​

    private double last_grade = 0;

    private int count = 0;

    private List<Record> courses = new List<Record>();

    public void Add(Record re)

    {

        courses.Add(re);

        count++;

        if (last_grade == 0)

            GPA = (last_grade + Convert.ToDouble(re.grade)) / count;

        else

            GPA = (last_grade * (count - 1) + Convert.ToDouble(re.grade)) / count;

        last_grade = GPA;

    }

​

    public int CompareTo(StudentRecord other)

    {

         if (this.GPA >= other.GPA)

             return -1;

        else if (this.GPA == other.GPA)

            return 0;

            else return 1;

    }

​

    public override string ToString()

    {

        return GPA.ToString();

    }

}

​

public class Program

{

    public static void Main()

    {

        List<StudentRecord> SList = new List<StudentRecord>();

        StudentRecord John = new StudentRecord();

        John.Add(new Record("IERG3080", "B"));

        John.Add(new Record("IERG3300", "A"));

        SList.Add(John);

        Console.WriteLine("John GPA :{0}", John.gpa);

        //

        StudentRecord Mary = new StudentRecord();

        Mary.Add(new Record("IERG3080", "A"));

        Mary.Add(new Record("IERG3300", "A"));

        Mary.Add(new Record("GEEC1000", "B"));

        SList.Add(Mary);

        Console.WriteLine("Mary GPA :{0}", Mary.gpa);

        //

        StudentRecord Joe = new StudentRecord();

        Joe.Add(new Record("IERG3080", "C"));

        Joe.Add(new Record("IERG3300", "B"));

        Joe.Add(new Record("ACAT1001", "C"));

        SList.Add(Joe);

        Console.WriteLine("Joe GPA :{0}", Joe.gpa);

        //

        StudentRecord Susie = new StudentRecord();

        Susie.Add(new Record("CSCI2100", "C"));

        Susie.Add(new Record("IERG2051", "F"));

        SList.Add(Susie);

        Console.WriteLine("Susie GPA :{0}", Susie.gpa);

        //

        SList.Sort();

        foreach (object GPA in SList)

            Console.WriteLine("GPA = {0}", GPA);

    }

}