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The Language of Programming
5:11Learn basic concepts shared by all programming languages — values, variables, functions and control structures. Learn how changing values can change how a program works by experimenting with a JavaScript game.
Launch the work space on this page and
then let's talk about programming.
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But before we get started,
take a look at all the words and
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symbols in front of you,
this is our program.
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Now, if you're beginning to panic because
it all looks like a foreign language and
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you're feeling like maybe this
is too difficult for you.
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Don't worry,
as I mentioned in the last video,
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you don't need to understand everything
you see here to have fun in this course.
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In fact, when we're done you still
won't understand everything here.
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This course is intended to just
give you a taste of programming.
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All you need to do is follow along,
experiment a little, and have fun.
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You can preview the webpage,
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this index.html file,
by clicking the preview button.
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Here's the current state of our game,
the score is zero,
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there's one coin,
one platform, and one player.
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The game.js file contains the programming
that makes our current game work
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It’s written in JavaScript, but
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there are literally hundreds of
different programming languages.
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All programing languages,
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however, share some basic features which
I'll introduce to you in this course.
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Syntax is the vocabulary, punctuation and
grammar of a programming language.
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The syntax includes key words which
are the languages vocabulary.
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For example, here var, function,
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And if are keywords in
the JavaScript language.
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They all have special meanings, and we'll
look at each of these in this course.
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Values, values are the data
in your program.
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They could be numbers,
like 375 Or 300 here.
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Or they could be letters inside
of quote marks, like 'coin'.
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This is called a string value, because
it's a set of letters strung together.
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There are many different types of values.
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Variables, variables hold values, they're
like boxes that you put a value into.
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You can look inside the box to
see the value it contains, and
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even replace the current
value with a new value.
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For example, in the last video,
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you saw that when a player collected
a coin, the score changed.
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The current score is a variable or
box in our game.
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A program uses these boxes to
pass information around and
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control what the program does and
how it works.
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The var keyword you see here,
in fact, is a JavaScript keyword,
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part of the syntax that creates
a variable named current score.
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The equal sign,
puts a value into a variable.
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So this code stores the value zero into
the variable named, current score.
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Change the score to 5000,
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Save the file, And preview it.
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The score's now 5000.
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Changing the value in
the variable changes the game.
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Hey let's look at another example.
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Let's go back to work space and
set the score back to zero.
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Notice this other variable named won,
as in I won the game.
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It's set to false, which is another
type of value, called a boolean.
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Let's change it to true.
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Save the file.
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And preview it.
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Look, you won the game!
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Okay, that doesn't make for
a very fun game, but
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you can see how values
affect how programs work.
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Changing this won variable to true changes
the information of our program and
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causes it to end the game.
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Working with data, values, and variables
is one of the most common features you'll
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use in any programming language.
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Let's set the value back to false and
save the file.
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Another feature of programming languages,
and programming in general,
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are control structures.
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Control structures control the flow
of the program, what happens and
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when it happens in a program.
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For example, in our game,
if we grab a coin, the score changes.
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Likewise, if the value of the variable
won is set to false, the player
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can run around the screen, jumping
onto platforms and collecting coins.
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However, when the value of one is true,
then a message appears on the screen and
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the game is over.
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These are both examples of a type
of control structure called
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a conditional statement.
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There are other types of
control structures but
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the important thing to keep in mind
is that we can control the flow or
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the steps a program follows
as the program runs.
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This is one of the things that makes
computer programs flexible and useful.
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Finally there are commands which
are often called functions.
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Functions are the heart of a program.
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They're the commands we ask
the computer to complete.
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A function can be as simple as adding two
numbers together, and giving you a result.
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Or it could be as complex as
adding information to a database.
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In the next video, I'll introduce you
to functions, as we build out our game
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