public YuksekLisans(string fullname, double tc, int age, Sube sube) : base(fullname, tc, age, sube)
 {
     this.fullname = tc + "-" + fullname;
     this.tc       = tc;
     this.age      = age;
     this.sube     = sube;
 }
 public Ogrenci(string fullname, double tc, int age, Sube sube) //nesne yaratılırken istenir.
 {
     this.fullname = tc + "-" + fullname;
     this.tc       = tc;
     this.age      = age;
     this.sube     = sube;
 }