Course E - Functions 1 - A Simple Function for a Superhero

Introduction

This lesson introduces the concept of functions. Functions are pieces of instructions or code that we know we will reuse. Instead of copying and pasting we use functions. We name our block of code and then any time we want to call the code we simply call the function by its name.

In this lesson, we will call a simple function and utilize the buttons to create actions a superhero might do.

Any time you want to repeat code, loops and functions should be considered. There are several benefits to using functions.

First, functions help us when we want to repeat code in many different places throughout our application. We only need to write it once and then call it by name. This benefit will be demonstrated more thoroughly in the second lesson of this series, 'FUNCTIONS FOR A DIGITAL PET'.

Because we are not repeating code so much, functions allow us to write code, which is smaller in size and easier to read. Also, making changes is easier.

Use the following example to highlight how much easier making changes with functions can be.

let KilometersRan = 0
input.onButtonPressed(Button.A, () => {
    Run_FasterThan_A_Speeding_Bullet()
    Run_FasterThan_A_Speeding_Bullet()
    Run_FasterThan_A_Speeding_Bullet()
    Run_FasterThan_A_Speeding_Bullet()
    Run_FasterThan_A_Speeding_Bullet()
})
input.onButtonPressed(Button.B, () => {
    KilometersRan = 5
    basic.showNumber(KilometersRan)
    basic.clearScreen()
    basic.pause(100)
    KilometersRan = 5
    basic.showNumber(KilometersRan)
    basic.clearScreen()
    basic.pause(100)
    KilometersRan = 5
    basic.showNumber(KilometersRan)
    basic.clearScreen()
    basic.pause(100)
    KilometersRan = 5
    basic.showNumber(KilometersRan)
    basic.clearScreen()
    basic.pause(100)
    KilometersRan = 5
    basic.showNumber(KilometersRan)
    basic.clearScreen()
    basic.pause(100)
})
function Run_FasterThan_A_Speeding_Bullet()  {
    KilometersRan = 5
    basic.showNumber(KilometersRan)
    basic.clearScreen()
    basic.pause(100)
}

Here the two buttons do exactly the same thing. If you press A or B they will will both show a blinking 5. Tell students to show a blinking 3 instead. How many changes do we need to make for button A?(1 change) How many changes do we need to make for button B?(5 changes!) Changing the function was much easier than the big block of code.

In our case the functions for our superhero help us accomplish another important benefit functions provide. Functions allow us to organize our code in meaningful ways that connect to the real life projects we program for. In this lesson, you will notice we are able to divide our code into actions our superhero might make. This makes it easier to think about the problem we want to solve and visualize the code working.

Instructors may consider doing the following with this first lesson on functions.

1. Focus on demonstrating at first. The students mostly watch and listen. (Initial code explanation / Challenge 1)
2. The teacher continues to do most of the lesson while the student helps. Teacher gives immediate feedback on the help. (Challenge 2 - Independent Practice)

For lesson two, 'FUNCTIONS FOR A DIGITAL PET', instructors can then either repeat the above or move on slowly allowing more responsibility to learners.

Of course this will depend on the students but scaffolding the learning in this manner may make these concepts easier to understand.

Our micro:bit course lessons are tailored to apply knowledge obtained from the Code.org CS Fundamentals. Before students begin this lesson, they are encouraged to first complete all CS Fundamentals as a prerequisite. Students should be familiar with functions from Code.org CS Fundamentals.

Background

Students are highly encouraged to first complete the following:

• Prerequisite Experience Starting Point
• Course E. CS Fundamentals. The course begins with a brief review of concepts previously taught in courses C and D. Students will practice coding with algorithms, loops, conditionals, events, and functions.

The teacher is highly encouraged to read below and complete the following:

• Teacher Quick Start Guide

Activity

What you'll need

• 1 - micro:bit
• 1 - USB cable
• 1 - AAA battery pack (optional)
• 2 - AAA batteries (optional)

Documentation

function doSomething()  {
    basic.showString("Hello!")
}

doSomething()
            

basic.showIcon(IconNames.Heart)

input.onGesture(Gesture.Shake, () => {

})
            

input.onButtonPressed(Button.A, () => {

})
            

let KeepRunning = false
let KilometersRan = 0
let XRunningPosition = 0
let YRunningPosition = 0
input.onButtonPressed(Button.A, () => {
    Run_FasterThan_A_Speeding_Bullet()
})
function Run_FasterThan_A_Speeding_Bullet()  {
    KilometersRan = 0
    KeepRunning = true
    XRunningPosition = 0
    YRunningPosition = 0
    for (let YRunningPosition = 0; YRunningPosition <= 5; YRunningPosition++) {
        for (let XRunningPosition = 0; XRunningPosition <= 5; XRunningPosition++) {
            led.plot(XRunningPosition, YRunningPosition)
            led.unplot(XRunningPosition - 1, YRunningPosition - 1)
            basic.pause(70)
        }
    }
}
input.onButtonPressed(Button.B, () => {
    MagicUsedToConjure()
})
function Object_Your_Superhero_Can_Conjure()  {

}
function MagicUsedToConjure()  {
    for (let index = 0; index <= 4; index++) {
        Object_Your_Superhero_Can_Conjure()
        basic.clearScreen()
        basic.pause(150)
    }
}

let YRunningPosition = 0
let XRunningPosition = 0
let KeepRunning = false
let KilometersRan = 0
input.onButtonPressed(Button.B, () => {
    MagicUsedToConjure()
})
function MagicUsedToConjure()  {
    for (let index = 0; index <= 4; index++) {
        Object_Your_Superhero_Can_Conjure()
        basic.clearScreen()
        basic.pause(150)
    }
}
function Object_Your_Superhero_Can_Conjure()  {
    basic.showIcon(IconNames.Ghost)
}
input.onButtonPressed(Button.A, () => {
    Run_FasterThan_A_Speeding_Bullet()
})
function Run_FasterThan_A_Speeding_Bullet()  {
    KilometersRan = 0
    KeepRunning = true
    XRunningPosition = 0
    YRunningPosition = 0
    for (let YRunningPosition2 = 0; YRunningPosition2 <= 5; YRunningPosition2++) {
        for (let XRunningPosition2 = 0; XRunningPosition2 <= 5; XRunningPosition2++) {
            led.plot(XRunningPosition2, YRunningPosition2)
            led.unplot(XRunningPosition2 - 1, YRunningPosition2 - 1)
            basic.pause(70)
        }
    }
}
input.onGesture(Gesture.Shake, () => {

})

let YRunningPosition = 0
let XRunningPosition = 0
let KeepRunning = false
let KilometersRan = 0
input.onButtonPressed(Button.B, () => {
    MagicUsedToConjure()
})
function MagicUsedToConjure()  {
    for (let index = 0; index <= 4; index++) {
        Object_Your_Superhero_Can_Conjure()
        basic.clearScreen()
        basic.pause(150)
    }
}
function Object_Your_Superhero_Can_Conjure()  {
    basic.showIcon(IconNames.Ghost)
}
input.onButtonPressed(Button.A, () => {
    Run_FasterThan_A_Speeding_Bullet()
})
function Run_FasterThan_A_Speeding_Bullet()  {
    KilometersRan = 0
    KeepRunning = true
    XRunningPosition = 0
    YRunningPosition = 0
    for (let YRunningPosition2 = 0; YRunningPosition2 <= 5; YRunningPosition2++) {
        for (let XRunningPosition2 = 0; XRunningPosition2 <= 5; XRunningPosition2++) {
            led.plot(XRunningPosition2, YRunningPosition2)
            led.unplot(XRunningPosition2 - 1, YRunningPosition2 - 1)
            basic.pause(70)
        }
    }
}
input.onGesture(Gesture.Shake, () => {
    basic.showIcon(IconNames.Surprised)
})

on shake
on button A pressed
on button B pressed

Game Console Functions
Start Game
Show Menu
Save Game
etc

Making Ice Cream Cone Functions
Choose Flavor
Grab Cone
Scoop Ice Cream
Put Scoop on Cone
EAT!!!

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