using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Intrinsics.X86;
using System.Text;
using System.Threading.Tasks;

namespace StudentenDatenbank
{
    internal class Datenbank
    {
        private Student[] studenten;

        public Datenbank(int anzahl) 
        { 
            studenten = new Student[anzahl];
        }
        public bool AddStudent(Student student) 
        {
            for (int i = 0; i < studenten.Length; i++)
            {
                if (studenten[i] == null)
                {
                    studenten[i] = student;
                    return true;
                }
            }
            return false;
        }
        public bool RemoveStudent(Student student) 
        {
            for (int i = 0; i < studenten.Length; i++)
            {
                if (studenten[i] == student) 
                {
                    studenten[i] = null;
                    return true;
                }
            }
            return false;
        }
        public bool RemoveStudent (int martrieklNr)
        {
            for (int i = 0; i < studenten.Length; i++)
            {
                if (studenten[i] != null)
                {
                    if (studenten[i].GetMatrikelNr() == martrieklNr)
                    {
                        studenten[i] = null;
                        return true;
                    }
                }
            }
            return false;
        }
        public int CountStudents()
        {
            int cnt = 0;
            for (int i = 0; i < studenten.Length; i++)
            {
                if (studenten[i] != null)
                {
                    cnt++;
                }
            }
            return cnt;
        }
        public void PrintMe()
        {
            for (int i = 0; i < studenten.Length; i++)
            {
                if (studenten[i] != null)
                {
                    studenten[i].PrintMe();
                }
            }
        }
    }
}