Variables in Programming
Introducing Variables to
store information?
Phil Bagge
Code-it-co-uk
Variables
Programming languages, like Scratch, need a way
to store information. They use a variable to do
this. Variables are like containers, boxes or
enverlopes.
Variables
Computers need a way to find the variable again.
So all variables need a label like these labels on
our containers.
labels
Inside a variable
We call what is inside a variable the value
2 chairs, 1 table, 1 sofa
1 teddy
3 keys
values
Reading a Variable
When a computer reads a variables label it
displays what is inside.
2 chairs, 1 table, 1 sofa
1 teddy
3 keys
Say Hello
var
friendname
how are you?
If a computer reads
this
it would display
this
Hello Mike how are you?
var
is our way of showing that
the next word is a variable
Set
var
friendname
to Mike
Say Hello
var
friendname
how are you?
Mike
friendname
Set puts the value into the variable
If a computer reads
this
it would display
this
Hello Mike how are you?
var
is our way of showing that
the next word is a variable
If a computer reads this what would it
display?
Set
var
friendname
to Milo
Say Hello
var
friendname
how are you?
Milo
friendname
Set puts the values into the variable
If a computer read this what would it
say?
Set
var
friendname
to Milo
Say Hello
var
friendname
how are you?
Milo
friendname
Hello Milo how are you?
If a computer read this what would it
say?
Set
var
myage
to 10
Say Hey, you are
var
myage.
10
myage
If a computer read this what would it
say?
Set
var
myage
to 10
Say Hey, you are
var
myage.
10
myage
Hey, you are 10.
If a computer read this what would it
say?
Set
var
friendname
to Lisa
Say Hello
var
friendname
how are you?
I think
var
friendname is such a cool
name. I wish I was called
var
friendname.
Lisa
friendname
If a computer read the variable more
than once what would it say?
Set
var
friendname
to Lisa
Say Hello
var
friendname,
how are you? I think
var
friendname is such a cool name. I wish I was called
var
friendname.
Hello Lisa, how are you? I think Lisa is such a cool name. I
wish I was called Lisa.
Lisa
friendname
Variable Fun
Create three variables with the following labels and your chosen values
Take turns to read this message to your partner
with the variables replaced with your values
Last night I ate
var
favnumber
pies.
I hate watching
var
footballteam
on TV as they always
lose by
var
favnumber
goals.
I am thinking of changing my name to
var
bestfriend
because it sounds much better than my name.
(No cheating read them exactly!)
Planning to use
var
name
Hello Bob good to see you.
You are looking good Bob.
I love what you have done with your hair Bob.
Write some
sentences that
use a short
name
Planning to use
var
name
Hello var name good to see you.
You are looking good var name.
I love what you have done with your hair var name.
Replace Bob
with var name
What is inside the variables?
If the user typed in
Mark what would be
inside
var
answer
and
var
name?
1
2
1
2
Work with your
partner to
examine this
program
Can you work
out how the
author used a
variable to
personalise it?
Where might you
use a name variable
in your Maths quiz?
What words, phrases or
questions would benefit
from having someone's
name included as well?
Discuss with your
partner
Recap starter
Work in pairs
One person holds the card so that only they can see it.
The person holding the card asks the first question
The other person provides an answer
The person holding the card then acts out the rest of the
program using the user input inside the variable
1, Which block is the input block
2, What is the variable called?
3, Will anyone say the word travel after the method has been chosen?
travel
No they will say the value that is inside the variable not the label that we can see
Variables in programming act as containers to store information. They are essential in languages like Scratch to hold values. Computers use labels to identify variables, and values stored inside can be accessed by reading the labels. Programming utilizes commands like "var" to define variables and set values. This introduction covers the basics of variables and their importance in programming.
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Presentation Transcript
Introducing Variables to store information? Phil Bagge Code-it-co-uk
Variables Programming languages, like Scratch, need a way to store information. They use a variable to do this. Variables are like containers, boxes or enverlopes.
Variables Computers need a way to find the variable again. So all variables need a label like these labels on our containers. keys labels
Inside a variable We call what is inside a variable the value toys keys furniture 3 keys 2 chairs, 1 table, 1 sofa 1 teddy values
Reading a Variable When a computer reads a variables label it displays what is inside. toys keys furniture 3 keys 2 chairs, 1 table, 1 sofa 1 teddy
var is our way of showing that the next word is a variable Say Hello var friendname how are you? If a computer reads this it would display this Hello Mike how are you?
var is our way of showing that the next word is a variable Set puts the value into the variable Set var friendname to Mike Say Hello var friendname how are you? friendname If a computer reads this it would display this Hello Mike how are you?
If a computer reads this what would it display? Set puts the values into the variable Set var friendname to Milo Say Hello var friendname how are you? friendname
If a computer read this what would it say? Set var friendname to Milo Say Hello var friendname how are you? Hello Milo how are you? friendname
If a computer read this what would it say? Set var myage to 10 Say Hey, you are var myage. myage
If a computer read this what would it say? Set var myage to 10 Say Hey, you are var myage. myage Hey, you are 10.
If a computer read this what would it say? Set var friendname to Lisa Say Hello var friendname how are you? I think var friendname is such a cool name. I wish I was called var friendname. friendname
If a computer read the variable more than once what would it say? Set var friendname to Lisa Say Hello var friendname, how are you? I think var friendname is such a cool name. I wish I was called var friendname. Hello Lisa, how are you? I think Lisa is such a cool name. I wish I was called Lisa. friendname
Variable Fun Create three variables with the following labels and your chosen values Label Value var bestfriend (you choose) var favnumber (you choose) var footballteam (you choose)
Take turns to read this message to your partner with the variables replaced with your values Last night I ate var favnumber pies. I hate watching var footballteam on TV as they always lose by var favnumber goals. I am thinking of changing my name to var bestfriend because it sounds much better than my name. (No cheating read them exactly!)
Write some sentences that use a short name Planning to use var name Hello Bob good to see you. You are looking good Bob. I love what you have done with your hair Bob.
Planning to use var name Replace Bob with var name Hello var name good to see you. You are looking good var name. I love what you have done with your hair var name.
What is inside the variables? If the user typed in Mark what would be inside var answer and var name?
1 2 2 1
Work with your partner to examine this program Can you work out how the author used a variable to personalise it?
Where might you use a name variable in your Maths quiz? What words, phrases or questions would benefit from having someone's name included as well? Discuss with your partner
1, Which block is the input block 2, What is the variable called? 3, Will anyone say the word travel after the method has been chosen? No they will say the value that is inside the variable not the label that we can see travel Recap starter Work in pairs One person holds the card so that only they can see it. The person holding the card asks the first question The other person provides an answer The person holding the card then acts out the rest of the program using the user input inside the variable
