How will you implement undo and redo option using the data structure?

How will you implement undo and redo option using the data structure?

Which data structure is used in redo-undo feature? Explanation: Stack data structure is most suitable to implement redo-undo feature. This is because the stack is implemented with LIFO(last in first out) order which is equivalent to redo-undo feature i.e. the last re-do is undo first.

How do you implement undo functionality?

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.

How do you reverse a traverse in a linked list?

Iterative Method

1. Initialize three pointers prev as NULL, curr as head and next as NULL.
2. Iterate through the linked list. In loop, do following. // Before changing next of current, // store next node. next = curr->next. // Now change next of current. // This is where actual reversing happens. curr->next = prev.

How do you implement undo and redo in Java?

Simply wrap the object in a new class and whenever its state changes, update it. The Command pattern stores the original object (that we want to support undo/redo) and the memento object, which we need in case of an undo.

How do you implement undo and redo in computer?

Undo

1. Undo is an interaction technique which is implemented in many computer programs.
2. In most Microsoft Windows applications, the keyboard shortcut for the undo command is Ctrl+Z or Alt+Backspace, and the shortcut for redo is Ctrl+Y or Ctrl+Shift+Z.

What are undo and redo operations?

The Redo command reverses the most recent change made using Undo. To undo an action, on the Edit menu, click Undo, or press Ctrl + Z. To redo an action, on the Edit menu, click Redo, or press Ctrl +Y.

Which of these patterns can be used to implement undo/redo operations?

Memento
There are two main software development patterns that are the obvious choices when dealing with operations like undo and redo: Memento and Command patterns.

How do you reverse traverse backwards in a singly linked list in Python?

Algorithm

1. Pass the head pointer to this method as node.
2. Check if the next node of node is None: If yes, this indicates that we have reached the end of the linked list. Set the head pointer to this node. If no, pass the next node of node to the reverse method.
3. Once the last node is reached, the reversing happens.

How do you return a linked list in Java?

Algorithm:

1. Start.
2. Declare a linked list of integer types without any initial size.
3. Use the add method to add the elements.
4. Append the elements at the end of the list.
5. Print the linked list elements before reversing.
6. Use the In-built Collections.
7. Print the linked list elements after reversing.
8. Stop.

How do you undo the last action in the document and then redo it?

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.

How do I go back to Ctrl Z?

To reverse your last action, press CTRL+Z. You can reverse more than one action. To reverse your last Undo, press CTRL+Y.

How do you implement undo/redo in Python?

To undo the last action, the last recently pushed element from the undo stack is popped and its undo method is executed. After that, the command is pushed onto the redo stack. To redo the last undone action, the last recently pushed element from the redo stack is popped and executed.