Workshop › Sudoku › Step 27 of 28

Tap the pad

What we are doing

A tap on a pad button writes that digit in the selected cell, and the last button erases.

```js
else if (y >= PAD_Y && y < PAD_Y + PAD_H && x >= 0 && x < 9 * SIZE) {
  const button = Math.floor(x / PAD_W)
  enter(button === 9 ? 0 : button + 1) // the last button erases
}
```

What it means

• A click that is not on the board is checked against the pad's rectangle.
• Math.floor(x / PAD_W) is the button's number, 0 to 9; buttons 0–8 are digits 1–9 and button 9 erases.

Your turn

In pointerdown, add the pad branch after the line that selects a cell.

Skills: Keyboard and mouse input

← A number pad Build it yourself: undo →

All steps

1. Nine by nine
2. Lines and boxes
3. A puzzle from a string
4. The puzzle's own digits
5. Keep drawing
6. The selected cell
7. Light up row, column and box
8. The same digit everywhere
9. Click to select
10. Move with the arrows
11. Write digits
12. The three rules in one loop
13. Show mistakes
14. Solved!
15. A clock
16. The solved message
17. Play again
18. The easiest cell
19. The solver
20. Random order
21. Invent a puzzle
22. A new puzzle every game
23. Hints
24. Best time
25. N for a new puzzle
26. A number pad
27. Tap the pad
28. Build it yourself: undo