Receiver (Document): ○ The Document class represents the receiver of the command. It contains the?

ctual operations for adding and removing text from the document. The

ddText and RemoveText methods manipulate the internal content (a

StringBuilder).
public class Document
{
private readonly StringBuilder _content = new StringBuilder();
public void AddText(string text) => _content.Append(text);
public void RemoveText(string text) =>

_content.Remove(_content.Length - text.Length, text.Length);

public override string ToString() => _content.ToString();
}