Undo and Redo Counter

How the Undo and Redo Counter Works

The Undo and Redo Counter stores each counting action in a history stack, so Undo reverses the most recent action and Redo restores it. Undo works for taps, subtractions, resets and step changes.

1. Count as normal: Each action, such as +1, +5 or Reset, goes onto the undo stack.
2. Press Undo: The last action is reversed and moved to the redo stack.
3. Press Redo: The undone action is applied again.
4. Make a new action: A new tap after an undo clears the redo stack.

Undo and Redo Counter Formula

The Undo and Redo Counter total equals the starting value plus the sum of all actions left on the undo stack.

Start

Value before the first action

Actions

Changes such as +1, +5 or −1

Example: Actions +1, +1, +5 and −1 give a total of 6. Undo removes −1, so the total becomes 7. Redo restores −1, and the total returns to 6.

Undo and Redo Counter Reference Table

The Undo and Redo Counter conversion table traces the total through a sample series of actions.

About the Undo and Redo Counter

An Undo and Redo Counter is a tally counter with a full action history that allows reversing and restoring changes. The history uses 2 stacks: one for undo and one for redo.

A plain −1 button fixes only single taps. Undo reverses any action, including an accidental Reset, which wipes out a long count on a counter without history.

Ways to Use the Undo and Redo Counter

There are 5 main uses of the Undo and Redo Counter, including reset recovery and step mistakes.

• ✓Reset recovery: Restore a long count after an accidental reset.
• ✓Step mistakes: Reverse a +10 tap that should have been +1.
• ✓Score disputes: Referees undo a point and redo it if the call stands.
• ✓Inventory corrections: Clerks reverse the last few entries after a recount.
• ✓Child use: Parents fix extra taps made by young children.