# 7 seconds game

### @explicitHints true

## Can you react at the right time? @unplugged

The goal of this game is press a button after **exactly** 7 seconds!

![A micro:bit looking at a 7 second stopwatch](/static/mb/projects/7-seconds.png)

This game is inspired from the [flipping pancakes game](https://www.elecfreaks.com/blog/post/flipping-pancakes-microbit-game.html).

## {Step 1}

The player starts the timer by pressing button **A**. Add the code to run code when
``||input:button A is pressed||``.

```spy
input.onButtonPressed(Button.A, function () {
	
})
```

## {Step 2}

We need to remember the time when the button was pressed so that we can compute the elapsed
time later on. Add code to store the ``||input:running time||`` in a ``||variables:start||``
variable.

```spy
let start = 0
input.onButtonPressed(Button.A, function () {
    // @highlight
    start = input.runningTime()
})
```

## {Step 3}

Show something on the screen so that the user knows that the timer has started...

```spy
let start = 0
input.onButtonPressed(Button.A, function () {
    start = input.runningTime()
    // @highlight
    basic.showIcon(IconNames.Chessboard)
})
```

## {Step 4}

The player stops the timer by pressing button **B**. Add another event to run code when
``||input:button B is pressed||``.

```spy
input.onButtonPressed(Button.B, function () {
	
})
```

## {Step 5}

Compute the elapsed time as ``||input:running time||`` ``||math:minus||`` ``||variables:start||`` and
store it in a new local variable (a variable only inside the event) called ``||variables:elapsed||``.

```spy
let start = 0
input.onButtonPressed(Button.B, function () {
    // @highlight
    let elapsed = input.runningTime() - start
})
```

## {Step 6}

Compute the ``||variables:score||`` of the game as the ``||math:absolute value||`` of the
``||math:difference||`` of ``||variables:elapsed||`` time from 7 seconds, which is `7000`
milliseconds.

```spy
let start = 0
input.onButtonPressed(Button.B, function () {
    let elapsed = input.runningTime() - start
    // @highlight
    let score = Math.abs(elapsed - 7000)
})
```

## {Step 7}

Display the score on the screen and your game is ready!

```spy
let start = 0
input.onButtonPressed(Button.B, function () {
    let elapsed = input.runningTime() - start
    let score = Math.abs(elapsed - 7000)
    // @highlight
    basic.showNumber(score)
})
```