String Editing Command Design Pattern

Use the Command pattern to implement string editing with undo/redo.

• Use an abstract Command base class.
• Implement and demonstrate command to append a letter to a string
• Implement and demonstrate command to delete a letter from the start of a string
• Implement and demonstrate command to delete a letter from the end of a string
• Implement and demonstrate command to capitalize a letter at any index within a string
• Implement and demonstrate command to lower case a letter at any index within a string
• Implement and demonstrate command to make a whole string use title case
• Implement an undo stack and demonstrate that all commands performed may be undone
• Implement an redo stack and demonstrate that all commands undone may be redone