using System;

class SetOfAccounts{

  public static void Main(){

    // Construct accounts:
    BankAccount ba1 = new BankAccount("John", 0.02),
                ba2 = new BankAccount("Anne", 0.02),
                ba3 = new BankAccount("Frank", 0.02);

    CheckAccount ca1 = new CheckAccount("Mike", 0.03),
                 ca2 = new CheckAccount("Lene", 0.03),
                 ca3 = new CheckAccount("Joan", 0.03);

    // Constructs empty sets of accounts:
    Set<BankAccount> s1 = new Set<BankAccount>();
    Set<CheckAccount> s2 = new Set<CheckAccount>();

    // Insert elements in the sets:
    s1.Insert(ba1);  s1.Insert(ba2);
    s2.Insert(ca1);  s2.Insert(ca2);

    // Establish s1 as an alias to s2
    s1 = s2;   // Compile-time error:
               // Cannot implicitly convert type 'Set<CheckAccount>' 
               // to 'Set<BankAccount>'

    // Insert a BankAccount object into s1, 
    // and via the alias also in s2
    s1.Insert(new BankAccount("Bodil", 0.02));

    // Activates some CheckAccount operation on a BankAccount object
    foreach(CheckAccount ca in s2)
      ca.SomeCheckAccountOperation();

    Console.WriteLine("Set of BankAccount: {0}", s1);
    Console.WriteLine("Set of CheckAccount: {0}", s2);
   

  }

}