pxt-calliope/docs/reference/js/lessons/jailbreak/challenges.md
2016-04-13 08:27:45 -07:00

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jailbreak challenges

Coding challenges for the jailbreak tutorial.#docs

Before we get started

Complete the following guided tutorial:

At the end of the tutorial, click keep editing. Your code should look like this:

count = 0
shouldBreak = false
input.onButtonPressed(Button.A, () => {
    shouldBreak = true
})
while (true) {
    if (shouldBreak) {
        basic.showString("I'M OUT!", 150)
        basic.plotImage(`
. # . # .
. # . # .
. . . . .
# . . . #
. # # # .
`)
        break
    }
    count = count + 1
    basic.showNumber(count, 150)
    basic.pause(1000)
}

Challenge 1

Try to remove the break in the if loop. What problem does this create?

Challenge 2

Now let's resume the timer again once button B is pressed! To do so, begin by creating a condition to know when button B is pressed.

// **. . .**
while (true) {
    if (shouldBreak) {
        basic.showString("I'M OUT!", 150)
        basic.plotImage(`
. # . # .
. # . # .
. . . . .
# . . . #
. # # # .
`)
        break
    }
    count = count + 1
    basic.showNumber(count, 150)
    basic.pause(1000)
}
input.onButtonPressed(Button.B, () => {
}) // ***

Next, set should break back to false to indicate we want to run the while loop again.

// **. . .**
input.onButtonPressed(Button.B, () => {
    shouldBreak = false // ***
})

And now copy the code from the previous while loop into the condition of input->on button pressed("B"). This will resume the counter.

// **. . .**
input.onButtonPressed(Button.B, () => {
    shouldBreak = false
    while (true) {
        if (shouldBreak) {
            basic.showString("I'M OUT!", 150) // ***
            basic.plotImage(`
. # . # .
. # . # .
. . . . .
# . . . #
. # # # .
`) // ***
            break // ***
        }
        count = count + 1 // ***
        basic.showNumber(count, 150) // ***
        basic.pause(1000) // ***
    }
})

Challenge 3

Notice that the two while loops are identical. Clean up this redundancy in your code by creating another method and then placing the while loop in the method.