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- [Instructor] Okay, so in this section,

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we are going to see how to use Cargo

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to create a new Rust application.

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Cargo is part of the Rust toolset.

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In practice, you will always use Cargo

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whenever you are creating
a Rust application

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or building it, or running it, okay?

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So, up until now I've been
writing a handcrafted Rust file

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and compiling it using the Rust compiler.

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You can do that,

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but it's better to use
Cargo for everything.

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So, it's the kind of one-stop shop

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for everything that
you want to do in Rust.

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It will generate an application initially,

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it'll give you a consistent
kind of directory structure

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and it nudges you towards
best practice, okay?

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So it's basically the tool
you should always be using

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whenever you are building,

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or creating, or running
a Rust application.

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So, like I said,

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it's included as part of
the standard Rust toolset.

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So if you've installed the Rust compiler,

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you've also installed Cargo already.

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This is how you can use Cargo

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to generate the new application.

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You say "cargo new"

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and then you give it the
name of the application.

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Rust prefers your
application to use lowercase

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and underscores.

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This is called snake case and
this is what Rust prefers.

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So I'm going to do that.

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I've already actually done
this in the demo package,

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let me show you.

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Here's the demo folder
for the current package

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for the current part of the demo.

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rustdev\lesson01_getting_started.

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And you'll notice

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that I've already got
hello_world_via_cargo.

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Okay, so we could look at that

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or we could generate a new application

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which is what I'm going to do instead.

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cargo new,

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and hello_world_via_cargo_2.

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That's going to be my new application.

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Okay, so that was quick.

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And what you'll find,

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it's generated a new folder
that contains that application.

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So I now have a new folder,

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hello_world_via_cargo_2.

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So, I'm gonna change into that directory,

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and let's see what we've got generated.

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So, it generates,

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well, it actually generates,

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you can't see it here,

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but it's generated a Git repository folder

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so that you can upload your application

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to a Git repository, or Bitbucket,

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and a .gitignore file

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specifying what files
not to upload to Git.

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All the source code is
in the source folder.

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And there's also a package
file called Cargo.toml

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which we're gonna have
a look at in a moment.

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Okay, so just a confirmation.

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This is what it actually looks like.

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There is a Git folder,
which is the Git repository,

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the source folder, which contains our code

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a .gitignore file,

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and then a toml file

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which contains basically
information about our application,

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what dependencies it has,

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what version number it is and suchlike.

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Okay, so this is the packaging file,

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containing metadata about our package

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and the list of any other libraries

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or any other dependencies
our application needs.

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The Rust library is fairly complete

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but there were third-party packages,

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third-party libraries,

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that you might also need to access.

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For example, if you're
talking to a database,

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you'll need to download some app packages

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that have database capabilities.

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So we'll have a look at how
to add additional dependencies

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into your application later.

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At the moment, this is what
the toml file looks like.

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Whatever the name of the
package is, the application,

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so for us it would be
hello_world_via_cargo_2,

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a version number, with kind
of like a release number

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and a major version and a minor version,

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that's up to you to manage.

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That's your number.

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You can change this as you like.

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And then the addition of the
Rust compiler that you're using

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as generated by the Cargo tool.

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So that's information about
your package, your application.

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And then this section here,

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dependencies is empty at the moment,

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but later on we'll be
adding entries in here

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which give us access to,

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for example there's a
library called Chrono

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for time manipulation.

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There's a library called MySQL
to access the MySQL database

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and so on.

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Okay, so later on in the video series,

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we'll be adding items underneath here

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to download libraries that
our application needs.

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Okay, so I'm gonna open my application,

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hello_world_via_cargo_2.

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I'm gonna open this one
in Visual Studio Code.

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And here it is.

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You see there's the toml file.

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And, as described,

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and here's the source file.

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And in the source file,

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we just have a single main.rs.

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Okay, as we would expect.

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So, we're kind of at the point now

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where we've generated the
application using Cargo,

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it has the source code,

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obviously we can add other source files

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in here if we wanted to.

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And it has the toml file,

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which we could edit if we wanted to,

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and then we could use Cargo

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to build the application
and to run the application.

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Okay, and that's what we're going to see

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in the next section.