Adding To A List From Another Class

I have a program which contains JuniorStudents and SeniorStudents. I've made seperate classes and in each class there is a list. Now when the student is year 6 or year 7 I shall promote it to senior student. I am doing this in the PromoteStudent method but when I call the ViewStudent method the SeniorStudent class I'm not getting the item. Can someone help me please? Here is the code:

Code:

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public class JuniorStudentsClass
002
    {
003
  public List<Student> mystudent = new List<Student>();
004
ublic void Addstudent()
005
        {
006
            Console.Write("enter students id:");
007
            s.Id = Int32.Parse(Console.ReadLine());
008
            Console.Write("enter students year:");
009
            s.Year = Int32.Parse(Console.ReadLine());
010
            Console.Write("enter name:");
011
            s.Name = Console.ReadLine();
012
            Console.Write("enter surname:");
013
            s.Surname = Console.ReadLine();
014
            Console.Write("enter dob:");
015
            s.DOB = Console.ReadLine();
016
            Console.Write("enter address:");
017
            s.Addr = Console.ReadLine();
018
            mystudent.Add(new Student(s.Id, s.Year, s.Name, s.Surname, s.DOB, s.Addr));
019
 
020
        }
021
 public void PromoteStudents(int index)
022
        {
023
            SearchItem(index);
024
            Console.WriteLine("current record:");
025
            Console.WriteLine("id is:" + mystudent[index].Id);
026
            Console.WriteLine("year is:" + mystudent[index].Year);
027
            Console.WriteLine("name is:" + mystudent[index].Name);
028
            Console.WriteLine("surname is:" + mystudent[index].Surname);
029
            Console.WriteLine("dob is:" + mystudent[index].DOB);
030
            Console.WriteLine("address is:" + mystudent[index].Addr);
031
            Console.WriteLine("enter new year of student to promote");
032
            s.Year = Int16.Parse(Console.ReadLine());
033
            if (((s.Year == 7)) || ((s.Year == 8)))
034
            {             
035
                sc.List.Add(new Student(mystudent[index].Id, s.Year, mystudent[index].Name, mystudent[index].Surname, mystudent[index].DOB, mystudent[index].Addr));
036
                Console.WriteLine("student promoted to senior student");
037
            }
038
            else
039
            {
040
                mystudent.Add(new Student(mystudent[index].Id, s.Year, mystudent[index].Name, mystudent[index].Surname, mystudent[index].DOB, mystudent[index].Addr));
041
                Console.WriteLine("student promoted to next year");
042
            }
043
        }
044
 
045
 
046
        public int SearchItem(int search)
047
        {
048
            int found = -1;
049
            if (mystudent != null)
050
            {
051
                foreach (Student st in mystudent)
052
                {
053
                    found++;
054
                    if (Student.Equals(search, st))
055
                    {
056
                        break;
057
                    }
058
 
059
                }
060
            }
061
            return found;
062
        }
063
 
064
public class SeniorStudentsClass
065
    {
066
        Student s = new Student();;
067
        public List<Student> studlist = new List<Student>();
068
 
069
        public List<Student> List {
070
            get { return studlist; }
071
            set { studlist = value; }
072
        }
073
 
074
        public void Addstudent()
075
        {
076
            Console.Write("enter students id:");
077
            s.Id = Int32.Parse(Console.ReadLine());
078
            Console.Write("enter students year:");
079
            s.Year = Int32.Parse(Console.ReadLine());
080
            Console.Write("enter name:");
081
            s.Name = Console.ReadLine();
082
            Console.Write("enter surname:");
083
            s.Surname = Console.ReadLine();
084
            Console.Write("enter dob:");
085
            s.DOB = Console.ReadLine();
086
            Console.Write("enter address:");
087
            s.Addr = Console.ReadLine();
088
            studlist.Add(new Student(s.Id, s.Year, s.Name, s.Surname, s.DOB, s.Addr)); 
089
 
090
        }  public void ViewStudents()
091
        {
092
            for (int i = 0; i < studlist.Count; i++)
093
            {
094
                Console.Write(studlist[i].Id + "\t");
095
                Console.Write(studlist[i].Year + "\t");
096
                Console.Write(studlist[i].Name + "\t");
097
                Console.Write(studlist[i].Surname + "\t");
098
                Console.Write(studlist[i].DOB + "\t");
099
                Console.Write(studlist[i].Addr);
100
                Console.WriteLine();
101
            }
102
        }
103
 
104
  public class Student
105
    {
106
        Marks mrk = new Marks();
107
        private int id;
108
        private string name;
109
        private string surname;
110
        private string dob;
111
        private string address;
112
        private int year;
113
 
114
        public Student()
115
        {
116
        }
117
        public Student(int id, int yr,string name, string surname, string dob, string address)
118
        {
119
            this.id = id;
120
            this.name = name;
121
            this.surname = surname;
122
            this.dob = dob;
123
            this.address = address;
124
            this.year = yr;
125
        }
126
 
127
     
128
      public string Name
129
        {
130
            get { return name; }
131
            set { name = value; }
132
        }
133
 
134
        public string Surname
135
        {
136
            get { return surname; }
137
            set { surname = value; }
138
 
139
        }
140
 
141
        public string DOB
142
        {
143
            get { return dob; }
144
            set { dob = value; }
145
        }
146
 
147
        public string Addr
148
        {
149
            get { return address; }
150
            set { address = value; }
151
 
152
        }
153
        public int Id
154
        {
155
            get { return id; }
156
            set { id = value; }
157
        }
158
 
159
 
160
        public int Year
161
        {
162
            get { return year; }
163
            set { year = value; }
164
 
165
        }

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I note your later post as well re same topic. If you care to post the complete code that complies and runs and produces the problem I'll have a look at it.