using System;

​

public class Program

{

    public static void Main()

    {

        Student s1 = new Student(1, "amir", 16);

        Student s2 = new Student(2, "fadi", 16);

        Student s3 = new Student(3, "ramy", 16);

        Student s4 = new Student(4, "faraj", 16);

        Student s5 = new Student(5, "tamer", 16);

        Classroom c1 = new Classroom("aoadim");

        c1.AddStudent(s1);

        c1.AddStudent(s2);

        c1.AddStudent(s3);

        c1.AddStudent(s4);

        c1.AddStudent(s5);

        Console.WriteLine(c1.GetStudentCount());

        c1.RemoveStudent(s5);

        Console.WriteLine(c1.GetStudentCount());

    }

}

​

public class Student

{

    private int id;

    private string name;

    private int age;

    public Student(int id, string name, int age)

    {

        this.id = id;

        this.name = name;

        this.age = age;

    }

​

    public int GetID()

    {

        return this.id;

    }

​

    public int GetAge()

    {

        return this.age;

    }

​

    public string GetName()

    {

        return this.name;

    }

​

    public void SetID(int id)

    {

        this.id = id;

    }

​

    public void SetAge(int age)

    {

        this.age = age;

    }

​

    public void SetName(string name)

    {

        this.name = name;

    }

}

​

public class Classroom

{

    private string ClassName;

    private Student[] Students;

    public Classroom(string ClassName)

    {

        this.ClassName = ClassName;

        this.Students = new Student[30];

    }

​

    public void AddStudent(Student s1)

    {

        for (int i = 0; i < Students.Length; i++)

        {

            if (Students[i] == null)

            {

                Students[i] = s1;

                return;

            }

        }

    }

​

    public void RemoveStudent(Student s)

    {

        for (int i=0;i<Students.Length;i++)

        {

            if (Students[i] != null)

            {

                if (Students[i].Equals(s))

                {

                    Students[i]=null;

                    return;

                }

            }

        }

        for (int i=0;i<Students.Length;i++)

        {

            if (Students[i] == null)

            {

                Students[i] = Students[i+1];

                for (int j=i; j<Students.Length; j++)

                {

                    if (Students[j+1] != null)

                    {

                        Students[j] = Students[j+1];

                    }

                }

            }

        }

    }

​

    public int GetStudentCount()

    {

        int c=0;

        for (int i=0; i<Students.Length;i++)

        {

            if (Students[i] != null)

            {

                c++;

            }

        }

        return c;

    }

}