Time based undo/redo?

1. What is the undo and Redo?
2. How do you implement redo and undo?
3. What is the action of redo?
4. How does the undo mechanism work?

What is the undo and Redo?

To undo an action, press Ctrl + Z. To redo an undone action, press Ctrl + Y. The Undo and Redo features let you remove or repeat single or multiple typing actions, but all actions must be undone or redone in the order you did or undid them – you can't skip actions.

How do you implement redo and undo?

If “UNDO” string is encountered, pop the top element from Undo stack and push it to Redo stack. If “REDO” string is encountered, pop the top element of Redo stack and push it into the Undo stack. If “READ” string is encountered, print all the elements of the Undo stack in reverse order.

What is the action of redo?

Redo an action

To redo something you've undone, press Ctrl+Y or F4. (If F4 doesn't seem to work, you may need to press the F-Lock key or Fn Key, then F4). If you prefer to use the mouse, click Redo on the Quick Access toolbar. (The Redo button only appears after you've undone an action.)

How does the undo mechanism work?

Undo is an interaction technique which is implemented in many computer programs. It erases the last change done to the document, reverting it to an older state. In some more advanced programs, such as graphic processing, undo will negate the last command done to the file being edited.