using System;

public class Student

{

    // 1. [Code] Create an auto-implementated property Name of type string 

    public string Name { get; set; }

    // 2. [Code] Create an auto-implementated property Age of type int 

    public int Age { get; set; }

    // 3. [Code] Create a private field _GPA of type double and a public property GPA

    //    where _GPA should never be negative.

    private double _GPA;

    public double GPA 

    { get { return _GPA; } 

        set 

        {

            if (value <0) Console.WriteLine("GPA cannot be set to a negative value ({0})", value);

            else _GPA = value;

        }

    }

    // 4. [Code] Create the first constructor with no parameters

    public Student() {}

​

    // 5. [Code] Create the second constructor with 3 parameters to set up the 3 properties

    public Student(string name, int age, double gpa) 

    {   Name = name;

        Age = age;

        GPA = gpa; 

    }

    // 6. [Code] Method ShowGPA

    //    Input: string strType, where "regular" or "adjusted" values are expected

    //    Output: return a double GPA value, where the return value is (GPA * 1.15) 

    //    when strType equals to "adjusted", otherwise return GPA

    //    Before you returning the GPA value, check whether GPA is greater than 4. If so, return 4.

    public double ShowGPA(string strType)

    {

        double val = GPA;

        if (strType == "adjusted") val *= 1.15;

        if (val > 4.0) val = 4.0;

        return val;

    }

    // 7. [Code] Method LuckyDraw

    //    Input: none

    //    Output: return a bool value whether student is lucky or not according to the rules:

    //    (1) sum up the number of characters of student's name and age.

    //    (2) return true if the number is divisible by 4; false, otherwise. (Hint: use %)

    public bool LuckyDraw()

    {

        return (Name.Length + Age) % 4 == 0;

    }

}

​

public class Program

{

    // Here is a static function

    public static void Function(int i, ref double d)

    {

        Console.WriteLine("Entering CallFunction: i = {0}, d = {1}", i, d);

        i++;

        d++;

        Console.WriteLine("Exiting CallFunction: i = {0}, d = {1}", i, d);

    }

    public static void Main()

    {

        // Here are some initial values

        string strName = "Mary";

        int iAge = 18;

        double dGPA = 3.6;

        // 8. [Code] Create a student object by using the values above.

        Student s = new Student(strName, iAge, dGPA);

        // 9. [Code] Call ShowGPA("regular"), and display return value

        Console.WriteLine(s.ShowGPA("regular"));

        // 10. [Code] Call ShowGPA("adjusted"), and display return value

        Console.WriteLine(s.ShowGPA("adjusted"));

        // 11. [Code] Call LuckyDraw, and display return value

        Console.WriteLine(s.LuckyDraw());

        Console.WriteLine("=================");

        /// 12. ***[Write your answer in the following comments]***

        Console.WriteLine("Age:{0}, GPA:{1}", iAge, dGPA);

        // What is the output of the code above?

        // ***Answer: Age:18, GPA:3.6

        Function(iAge, ref dGPA);

        // 13. ***[Write your answer in the following comments]***

        Console.WriteLine("Age:{0}, GPA:{1}", iAge, dGPA);

        // What is the output of the code above?

        // ***Answer: Age:18, GPA:4.6

        // Why is one variable incremented and the other is not?

        // ***Answer: In the Function method, iAge is passed by value, preserving its original value outside the method. 

        // However, dGPA is passed by reference, allowing direct modification. As a result, iAge remains the same, while dGPA gets incremented.

    }

}