Workshop › Battleship › Step 22 of 35

The computer shoots back

What we are doing

Now the computer plays: when its timer runs out, it picks a random square on your sea it has not shot yet, fires, and gives the turn back.

```js
function computerShoots() {
  let r
  let c
  do {
    r = Math.floor(Math.random() * N)
    c = Math.floor(Math.random() * N)
  } while (theirShots[r][c])
  const result = fire(myFleet, theirShots, r, c)
  message = result === 'sunk' ? 'They sank your ship!' : 'Your turn: pick a square'
  turn = 'you'
}

function update() {
  if (state === 'playing' && turn === 'them' && --timer === 0) computerShoots()
}

  update()
```

What it means

The do ... while keeps picking a random square until it finds one not shot yet.
It fires with the same fire function you use, on your fleet and its own record.
--timer subtracts 1 first and then compares: after 30 frames it reaches 0 and the computer shoots.

Your turn

Under playerShoots, write computerShoots and update.
In loop, call update() before draw().

Skills: The game loop, Loops

← Take turns You can lose too →

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