using System;

using System.Collections.Generic;

public class StudentRecord: IComparable<StudentRecord>{  //remember to put in <>

    string name;

    double cGPA;

    Dictionary<string, string> scores; 

    static Dictionary<string, double> gradeToGPA = new Dictionary<string, double>(){

        {"A", 4.0} , {"B", 3.3}, {"C", 2.7}, {"F", 0}

    };

    public StudentRecord(string pName){

        name = pName;

        scores = new Dictionary<string, string>(); //need to initiate first to make sure AddCourse will work well

        cGPA = 0;

    }

    public void AddCourse(string pCourse, string pGrade){

        scores.Add(pCourse, pGrade);

    }

    public double CalculateGPA(){

        double sumGPA = 0;

        int courseCount = 0;

        foreach(KeyValuePair<string, string> pair in scores)

        {

            sumGPA += gradeToGPA[scores[pair.Key]];

            courseCount += 1;

        }

        cGPA = sumGPA / courseCount;

        return cGPA;

    }

    public int CompareTo(StudentRecord s){

        double e = 0.0000001;

        if (cGPA > s.cGPA) return 1;

        else if ( Math.Abs(cGPA -  s.cGPA) < e ) return 0;

        else return -1;

    }

    public override string ToString(){ //need override

        return name;

    }

    public double CGPA{

        get {return cGPA;}

    }

}

​

​

public class Program

{

    public static void Main()

    {

        StudentRecord john = new StudentRecord("John");

        john.AddCourse("IERG3080", "B");

        john.AddCourse("IERG3300", "A");

        StudentRecord mary = new StudentRecord("Mary");

        mary.AddCourse("IERG3080", "A");

        mary.AddCourse("IERG3300", "A");

        StudentRecord joe = new StudentRecord("Joe");

        joe.AddCourse("IERG3080", "C");

        joe.AddCourse("IERG3300", "B");

        joe.AddCourse("ACAT1001", "C");

        StudentRecord susie = new StudentRecord("Susie");

        susie.AddCourse("CSCI2100", "C");

        susie.AddCourse("IERG2051", "F");

        john.CalculateGPA();

        mary.CalculateGPA();

        joe.CalculateGPA();

        susie.CalculateGPA();

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

        studentList.Add(john);

        studentList.Add(mary);

        studentList.Add(joe);

        studentList.Add(susie);

        studentList.Sort();

        foreach(StudentRecord s in studentList)

        {

            Console.WriteLine("{0}'s GPA is {1}", s, s.CGPA);

        }

    }

}