pxt-calliope/docs/reference/js/lessons/digi-yoyo/challenges.md

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2016-03-26 00:47:20 +01:00
# digi yoyo challenges
Coding challenges for the digi yoyo.
## Before we get started
Complete the following guided tutorial:
* [tutorial](/microbit/lessons/digi-yoyo/tutorial)
At the end of the tutorial, click `keep editing`. Your code should look like this:
```
let count = 0
while (count < 10) {
basic.pause(1000)
basic.showNumber(count, 150)
count = count + 1
}
```
### Challenge 1
How about we create a counter that counts backwards from 10 to 1? Let's add a while loop that executes only when `count` is greater than 0.
```
let count1 = 0
while (count1 < 10) {
basic.pause(1000)
basic.showNumber(count1, 150)
count1 = count1 + 1
}
while (count1 > 0) {
}
```
### Challenge 2
### @video td/videos/digi-yoyo-1-2
Inside of the while loop, let's add `pause->(1000)` so that we have a pause between each number as it's counting down. Also, let's show `count`!
```
let count2 = 0
while (count2 < 10) {
basic.pause(1000)
basic.showNumber(count2, 150)
count2 = count2 + 1
}
while (count2 > 0) {
basic.pause(1000) // ***
basic.showNumber(count2, 150) // ***
}
```
* Run the code to see if it works as expected.
### Challenge 3
Now, we need `count` to decrease by one after the BBC micro:bit has displayed the value of `count`.
We can do this by adding this line:
`count := count - 1`