//
//   This file contains the C# code from Program 5.13 of
//   "Data Structures and Algorithms
//    with Object-Oriented Design Patterns in C#"
//   by Bruno R. Preiss.
//
//   Copyright (c) 2001--2002 by Bruno R. Preiss, P.Eng.  All rights reserved.
//
//   http://www.brpreiss.com/books/opus6/programs/pgm05_13.txt
//
public abstract class AbstractContainer :
    ComparableObject, Container
{
    protected int count;

    private class ToStringVisitor : AbstractVisitor
    {
	StringBuilder builder = new StringBuilder();
	private bool comma = false;

	public override void Visit(object obj)
	{
	    if (comma)
		builder.Append(", ");
	    builder.Append(obj);
	    comma = true;
	}

	public override string ToString()
	    { return builder.ToString(); }
    };

    public override string ToString()
    {
	Visitor visitor = new ToStringVisitor();
	Accept(visitor);
	return GetType().FullName + " {" + visitor + "}";
    }
    // ...
}