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<ol class="chapter"><li class="expanded affix "><a href="title-page.html">The Rust Programming Language</a></li><li class="expanded affix "><a href="foreword.html">Foreword</a></li><li class="expanded affix "><a href="ch00-00-introduction.html">Introduction</a></li><li class="expanded "><a href="ch01-00-getting-started.html"><strong aria-hidden="true">1.</strong> Getting Started</a></li><li><ol class="section"><li class="expanded "><a href="ch01-01-installation.html"><strong aria-hidden="true">1.1.</strong> Installation</a></li><li class="expanded "><a href="ch01-02-hello-world.html" class="active"><strong aria-hidden="true">1.2.</strong> Hello, World!</a></li><li class="expanded "><a href="ch01-03-hello-cargo.html"><strong aria-hidden="true">1.3.</strong> Hello, Cargo!</a></li></ol></li><li class="expanded "><a href="ch02-00-guessing-game-tutorial.html"><strong aria-hidden="true">2.</strong> Programming a Guessing Game</a></li><li class="expanded "><a href="ch03-00-common-programming-concepts.html"><strong aria-hidden="true">3.</strong> Common Programming Concepts</a></li><li><ol class="section"><li class="expanded "><a href="ch03-01-variables-and-mutability.html"><strong aria-hidden="true">3.1.</strong> Variables and Mutability</a></li><li class="expanded "><a href="ch03-02-data-types.html"><strong aria-hidden="true">3.2.</strong> Data Types</a></li><li class="expanded "><a href="ch03-03-how-functions-work.html"><strong aria-hidden="true">3.3.</strong> Functions</a></li><li class="expanded "><a href="ch03-04-comments.html"><strong aria-hidden="true">3.4.</strong> Comments</a></li><li class="expanded "><a href="ch03-05-control-flow.html"><strong aria-hidden="true">3.5.</strong> Control Flow</a></li></ol></li><li class="expanded "><a href="ch04-00-understanding-ownership.html"><strong aria-hidden="true">4.</strong> Understanding Ownership</a></li><li><ol class="section"><li class="expanded "><a href="ch04-01-what-is-ownership.html"><strong aria-hidden="true">4.1.</strong> What is Ownership?</a></li><li class="expanded "><a href="ch04-02-references-and-borrowing.html"><strong aria-hidden="true">4.2.</strong> References and Borrowing</a></li><li class="expanded "><a href="ch04-03-slices.html"><strong aria-hidden="true">4.3.</strong> The Slice Type</a></li></ol></li><li class="expanded "><a href="ch05-00-structs.html"><strong aria-hidden="true">5.</strong> Using Structs to Structure Related Data</a></li><li><ol class="section"><li class="expanded "><a href="ch05-01-defining-structs.html"><strong aria-hidden="true">5.1.</strong> Defining and Instantiating Structs</a></li><li class="expanded "><a href="ch05-02-example-structs.html"><strong aria-hidden="true">5.2.</strong> An Example Program Using Structs</a></li><li class="expanded "><a href="ch05-03-method-syntax.html"><strong aria-hidden="true">5.3.</strong> Method Syntax</a></li></ol></li><li class="expanded "><a href="ch06-00-enums.html"><strong aria-hidden="true">6.</strong> Enums and Pattern Matching</a></li><li><ol class="section"><li class="expanded "><a href="ch06-01-defining-an-enum.html"><strong aria-hidden="true">6.1.</strong> Defining an Enum</a></li><li class="expanded "><a href="ch06-02-match.html"><strong aria-hidden="true">6.2.</strong> The match Control Flow Operator</a></li><li class="expanded "><a href="ch06-03-if-let.html"><strong aria-hidden="true">6.3.</strong> Concise Control Flow with if let</a></li></ol></li><li class="expanded "><a href="ch07-00-managing-growing-projects-with-packages-crates-and-modules.html"><strong aria-hidden="true">7.</strong> Managing Growing Projects with Packages, Crates, and Modules</a></li><li><ol class="section"><li class="expanded "><a href="ch07-01-packages-and-crates.html"><strong aria-hidden="true">7.1.</strong> Packages and Crates</a></li><li class="expanded "><a href="ch07-02-defining-modules-to-control-scope-and-privacy.html"><strong aria-hidden="true">7.2.</strong> Defining Modules to Control Scope and Privacy</a></li><li class="expanded "><a href="ch07-03-paths-for-referring-to-an-item-in-the-module-tree.html"><strong aria-hidden="true">7.3.</strong> Paths for Referring to an Item in the Module Tree</a></li><li class="expanded "><a href="ch07-04-bringing-paths-into-scope-with-the-use-keyword.html"><strong aria-hidden="true">7.4.</strong> Bringing Paths Into Scope with the use Keyword</a></li><li class="expanded "><a href="ch07-05-separating-modules-into-different-files.html"><strong aria-hidden="true">7.5.</strong> Separating Modules into Different Files</a></li></ol></li><li class="expanded "><a href="ch08-00-common-collections.html"><strong aria-hidden="true">8.</strong> Common Collections</a></li><li><ol class="section"><li class="expanded "><a href="ch08-01-vectors.html"><strong aria-hidden="true">8.1.</strong> Storing Lists of Values with Vectors</a></li><li class="expanded "><a href="ch08-02-strings.html"><strong aria-hidden="true">8.2.</strong> Storing UTF-8 Encoded Text with Strings</a></li><li class="expanded "><a href="ch08-03-hash-maps.html"><strong aria-hidden="true">8.3.</strong> Storing Keys with Associated Values in Hash Maps</a></li></ol></li><li class="expanded "><a href="ch09-00-error-handling.html"><strong aria-hidden="true">9.</strong> Error Handling</a></li><li><ol class="section"><li class="expanded "><a href="ch09-01-unrecoverable-errors-with-panic.html"><strong aria-hidden="true">9.1.</strong> Unrecoverable Errors with panic!</a></li><li class="expanded "><a href="ch09-02-recoverable-errors-with-result.html"><strong aria-hidden="true">9.2.</strong> Recoverable Errors with Result</a></li><li class="expanded "><a href="ch09-03-to-panic-or-not-to-panic.html"><strong aria-hidden="true">9.3.</strong> To panic! or Not To panic!</a></li></ol></li><li class="expanded "><a href="ch10-00-generics.html"><strong aria-hidden="true">10.</strong> Generic Types, Traits, and Lifetimes</a></li><li><ol class="section"><li class="expanded "><a href="ch10-01-syntax.html"><strong aria-hidden="true">10.1.</strong> Generic Data Types</a></li><li class="expanded "><a href="ch10-02-traits.html"><strong aria-hidden="true">10.2.</strong> Traits: Defining Shared Behavior</a></li><li class="expanded "><a href="ch10-03-lifetime-syntax.html"><strong aria-hidden="true">10.3.</strong> Validating References with Lifetimes</a></li></ol></li><li class="expanded "><a href="ch11-00-testing.html"><strong aria-hidden="true">11.</strong> Writing Automated Tests</a></li><li><ol class="section"><li class="expanded "><a href="ch11-01-writing-tests.html"><strong aria-hidden="true">11.1.</strong> How to Write Tests</a></li><li class="expanded "><a href="ch11-02-running-tests.html"><strong aria-hidden="true">11.2.</strong> Controlling How Tests Are Run</a></li><li class="expanded "><a href="ch11-03-test-organization.html"><strong aria-hidden="true">11.3.</strong> Test Organization</a></li></ol></li><li class="expanded "><a href="ch12-00-an-io-project.html"><strong aria-hidden="true">12.</strong> An I/O Project: Building a Command Line Program</a></li><li><ol class="section"><li class="expanded "><a href="ch12-01-accepting-command-line-arguments.html"><strong aria-hidden="true">12.1.</strong> Accepting Command Line Arguments</a></li><li class="expanded "><a href="ch12-02-reading-a-file.html"><strong aria-hidden="true">12.2.</strong> Reading a File</a></li><li class="expanded "><a href="ch12-03-improving-error-handling-and-modularity.html"><strong aria-hidden="true">12.3.</strong> Refactoring to Improve Modularity and Error Handling</a></li><li class="expanded "><a href="ch12-04-testing-the-librarys-functionality.html"><strong aria-hidden="true">12.4.</strong> Developing the Library’s Functionality with Test Driven Development</a></li><li class="expanded "><a href="ch12-05-working-with-environment-variables.html"><strong aria-hidden="true">12.5.</strong> Working with Environment Variables</a></li><li class="expanded "><a href="ch12-06-writing-to-stderr-instead-of-stdout.html"><strong aria-hidden="true">12.6.</strong> Writing Error Messages to Standard Error Instead of Standard Output</a></li></ol></li><li class="expanded "><a href="ch13-00-functional-features.html"><strong aria-hidden="true">13.</strong> Functional Language Features: Iterators and Closures</a></li><li><ol class="section"><li class="expanded "><a href="ch13-01-closures.html"><strong aria-hidden="true">13.1.</strong> Closures: Anonymous Functions that Can Capture Their Environment</a></li><li class="expanded "><a href="ch13-02-iterators.html"><strong aria-hidden="true">13.2.</strong> Processing a Series of Items with Iterators</a></li><li class="expanded "><a href="ch13-03-improving-our-io-project.html"><strong aria-hidden="true">13.3.</strong> Improving Our I/O Project</a></li><li class="expanded "><a href="ch13-04-performance.html"><strong aria-hidden="true">13.4.</strong> Comparing Performance: Loops vs. Iterators</a></li></ol></li><li class="expanded "><a href="ch14-00-more-about-cargo.html"><strong aria-hidden="true">14.</strong> More about Cargo and Crates.io</a></li><li><ol class="section"><li class="expanded "><a href="ch14-01-release-profiles.html"><strong aria-hidden="true">14.1.</strong> Customizing Builds with Release Profiles</a></li><li class="expanded "><a href="ch14-02-publishing-to-crates-io.html"><strong aria-hidden="true">14.2.</strong> Publishing a Crate to Crates.io</a></li><li class="expanded "><a href="ch14-03-cargo-workspaces.html"><strong aria-hidden="true">14.3.</strong> Cargo Workspaces</a></li><li class="expanded "><a href="ch14-04-installing-binaries.html"><strong aria-hidden="true">14.4.</strong> Installing Binaries from Crates.io with cargo install</a></li><li class="expanded "><a href="ch14-05-extending-cargo.html"><strong aria-hidden="true">14.5.</strong> Extending Cargo with Custom Commands</a></li></ol></li><li class="expanded "><a href="ch15-00-smart-pointers.html"><strong aria-hidden="true">15.</strong> Smart Pointers</a></li><li><ol class="section"><li class="expanded "><a href="ch15-01-box.html"><strong aria-hidden="true">15.1.</strong> Using Box<T> to Point to Data on the Heap</a></li><li class="expanded "><a href="ch15-02-deref.html"><strong aria-hidden="true">15.2.</strong> Treating Smart Pointers Like Regular References with the Deref Trait</a></li><li class="expanded "><a href="ch15-03-drop.html"><strong aria-hidden="true">15.3.</strong> Running Code on Cleanup with the Drop Trait</a></li><li class="expanded "><a href="ch15-04-rc.html"><strong aria-hidden="true">15.4.</strong> Rc<T>, the Reference Counted Smart Pointer</a></li><li class="expanded "><a href="ch15-05-interior-mutability.html"><strong aria-hidden="true">15.5.</strong> RefCell<T> and the Interior Mutability Pattern</a></li><li class="expanded "><a href="ch15-06-reference-cycles.html"><strong aria-hidden="true">15.6.</strong> Reference Cycles Can Leak Memory</a></li></ol></li><li class="expanded "><a href="ch16-00-concurrency.html"><strong aria-hidden="true">16.</strong> Fearless Concurrency</a></li><li><ol class="section"><li class="expanded "><a href="ch16-01-threads.html"><strong aria-hidden="true">16.1.</strong> Using Threads to Run Code Simultaneously</a></li><li class="expanded "><a href="ch16-02-message-passing.html"><strong aria-hidden="true">16.2.</strong> Using Message Passing to Transfer Data Between Threads</a></li><li class="expanded "><a href="ch16-03-shared-state.html"><strong aria-hidden="true">16.3.</strong> Shared-State Concurrency</a></li><li class="expanded "><a href="ch16-04-extensible-concurrency-sync-and-send.html"><strong aria-hidden="true">16.4.</strong> Extensible Concurrency with the Sync and Send Traits</a></li></ol></li><li class="expanded "><a href="ch17-00-oop.html"><strong aria-hidden="true">17.</strong> Object Oriented Programming Features of Rust</a></li><li><ol class="section"><li class="expanded "><a href="ch17-01-what-is-oo.html"><strong aria-hidden="true">17.1.</strong> Characteristics of Object-Oriented Languages</a></li><li class="expanded "><a href="ch17-02-trait-objects.html"><strong aria-hidden="true">17.2.</strong> Using Trait Objects That Allow for Values of Different Types</a></li><li class="expanded "><a href="ch17-03-oo-design-patterns.html"><strong aria-hidden="true">17.3.</strong> Implementing an Object-Oriented Design Pattern</a></li></ol></li><li class="expanded "><a href="ch18-00-patterns.html"><strong aria-hidden="true">18.</strong> Patterns and Matching</a></li><li><ol class="section"><li class="expanded "><a href="ch18-01-all-the-places-for-patterns.html"><strong aria-hidden="true">18.1.</strong> All the Places Patterns Can Be Used</a></li><li class="expanded "><a href="ch18-02-refutability.html"><strong aria-hidden="true">18.2.</strong> Refutability: Whether a Pattern Might Fail to Match</a></li><li class="expanded "><a href="ch18-03-pattern-syntax.html"><strong aria-hidden="true">18.3.</strong> Pattern Syntax</a></li></ol></li><li class="expanded "><a href="ch19-00-advanced-features.html"><strong aria-hidden="true">19.</strong> Advanced Features</a></li><li><ol class="section"><li class="expanded "><a href="ch19-01-unsafe-rust.html"><strong aria-hidden="true">19.1.</strong> Unsafe Rust</a></li><li class="expanded "><a href="ch19-03-advanced-traits.html"><strong aria-hidden="true">19.2.</strong> Advanced Traits</a></li><li class="expanded "><a href="ch19-04-advanced-types.html"><strong aria-hidden="true">19.3.</strong> Advanced Types</a></li><li class="expanded "><a href="ch19-05-advanced-functions-and-closures.html"><strong aria-hidden="true">19.4.</strong> Advanced Functions and Closures</a></li><li class="expanded "><a href="ch19-06-macros.html"><strong aria-hidden="true">19.5.</strong> Macros</a></li></ol></li><li class="expanded "><a href="ch20-00-final-project-a-web-server.html"><strong aria-hidden="true">20.</strong> Final Project: Building a Multithreaded Web Server</a></li><li><ol class="section"><li class="expanded "><a href="ch20-01-single-threaded.html"><strong aria-hidden="true">20.1.</strong> Building a Single-Threaded Web Server</a></li><li class="expanded "><a href="ch20-02-multithreaded.html"><strong aria-hidden="true">20.2.</strong> Turning Our Single-Threaded Server into a Multithreaded Server</a></li><li class="expanded "><a href="ch20-03-graceful-shutdown-and-cleanup.html"><strong aria-hidden="true">20.3.</strong> Graceful Shutdown and Cleanup</a></li></ol></li><li class="expanded "><a href="appendix-00.html"><strong aria-hidden="true">21.</strong> Appendix</a></li><li><ol class="section"><li class="expanded "><a href="appendix-01-keywords.html"><strong aria-hidden="true">21.1.</strong> A - Keywords</a></li><li class="expanded "><a href="appendix-02-operators.html"><strong aria-hidden="true">21.2.</strong> B - Operators and Symbols</a></li><li class="expanded "><a href="appendix-03-derivable-traits.html"><strong aria-hidden="true">21.3.</strong> C - Derivable Traits</a></li><li class="expanded "><a href="appendix-04-useful-development-tools.html"><strong aria-hidden="true">21.4.</strong> D - Useful Development Tools</a></li><li class="expanded "><a href="appendix-05-editions.html"><strong aria-hidden="true">21.5.</strong> E - Editions</a></li><li class="expanded "><a href="appendix-06-translation.html"><strong aria-hidden="true">21.6.</strong> F - Translations of the Book</a></li><li class="expanded "><a href="appendix-07-nightly-rust.html"><strong aria-hidden="true">21.7.</strong> G - How Rust is Made and “Nightly Rust”</a></li></ol></li></ol>
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<h1 class="menu-title">The Rust Programming Language</h1>
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<h2><a class="header" href="#hello-world" id="hello-world">Hello, World!</a></h2>
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<p>Now that you’ve installed Rust, let’s write your first Rust program. It’s
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traditional when learning a new language to write a little program that prints
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the text <code>Hello, world!</code> to the screen, so we’ll do the same here!</p>
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<blockquote>
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<p>Note: This book assumes basic familiarity with the command line. Rust makes
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no specific demands about your editing or tooling or where your code lives, so
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if you prefer to use an integrated development environment (IDE) instead of
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the command line, feel free to use your favorite IDE. Many IDEs now have some
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degree of Rust support; check the IDE’s documentation for details. Recently,
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the Rust team has been focusing on enabling great IDE support, and progress
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has been made rapidly on that front!</p>
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|
||
<h3><a class="header" href="#creating-a-project-directory" id="creating-a-project-directory">Creating a Project Directory</a></h3>
|
||
<p>You’ll start by making a directory to store your Rust code. It doesn’t matter
|
||
to Rust where your code lives, but for the exercises and projects in this book,
|
||
we suggest making a <em>projects</em> directory in your home directory and keeping all
|
||
your projects there.</p>
|
||
<p>Open a terminal and enter the following commands to make a <em>projects</em> directory
|
||
and a directory for the “Hello, world!” project within the <em>projects</em> directory.</p>
|
||
<p>For Linux, macOS, and PowerShell on Windows, enter this:</p>
|
||
<pre><code class="language-text">$ mkdir ~/projects
|
||
$ cd ~/projects
|
||
$ mkdir hello_world
|
||
$ cd hello_world
|
||
</code></pre>
|
||
<p>For Windows CMD, enter this:</p>
|
||
<pre><code class="language-cmd">> mkdir "%USERPROFILE%\projects"
|
||
> cd /d "%USERPROFILE%\projects"
|
||
> mkdir hello_world
|
||
> cd hello_world
|
||
</code></pre>
|
||
<h3><a class="header" href="#writing-and-running-a-rust-program" id="writing-and-running-a-rust-program">Writing and Running a Rust Program</a></h3>
|
||
<p>Next, make a new source file and call it <em>main.rs</em>. Rust files always end with
|
||
the <em>.rs</em> extension. If you’re using more than one word in your filename, use
|
||
an underscore to separate them. For example, use <em>hello_world.rs</em> rather than
|
||
<em>helloworld.rs</em>.</p>
|
||
<p>Now open the <em>main.rs</em> file you just created and enter the code in Listing 1-1.</p>
|
||
<p><span class="filename">Filename: main.rs</span></p>
|
||
<pre><pre class="playpen"><code class="language-rust">fn main() {
|
||
println!("Hello, world!");
|
||
}
|
||
</code></pre></pre>
|
||
<p><span class="caption">Listing 1-1: A program that prints <code>Hello, world!</code></span></p>
|
||
<p>Save the file and go back to your terminal window. On Linux or macOS, enter
|
||
the following commands to compile and run the file:</p>
|
||
<pre><code class="language-text">$ rustc main.rs
|
||
$ ./main
|
||
Hello, world!
|
||
</code></pre>
|
||
<p>On Windows, enter the command <code>.\main.exe</code> instead of <code>./main</code>:</p>
|
||
<pre><code class="language-powershell">> rustc main.rs
|
||
> .\main.exe
|
||
Hello, world!
|
||
</code></pre>
|
||
<p>Regardless of your operating system, the string <code>Hello, world!</code> should print to
|
||
the terminal. If you don’t see this output, refer back to the
|
||
<a href="ch01-01-installation.html#troubleshooting">“Troubleshooting”</a><!-- ignore --> part of the Installation
|
||
section for ways to get help.</p>
|
||
<p>If <code>Hello, world!</code> did print, congratulations! You’ve officially written a Rust
|
||
program. That makes you a Rust programmer—welcome!</p>
|
||
<h3><a class="header" href="#anatomy-of-a-rust-program" id="anatomy-of-a-rust-program">Anatomy of a Rust Program</a></h3>
|
||
<p>Let’s review in detail what just happened in your “Hello, world!” program.
|
||
Here’s the first piece of the puzzle:</p>
|
||
<pre><pre class="playpen"><code class="language-rust">fn main() {
|
||
|
||
}
|
||
</code></pre></pre>
|
||
<p>These lines define a function in Rust. The <code>main</code> function is special: it is
|
||
always the first code that runs in every executable Rust program. The first
|
||
line declares a function named <code>main</code> that has no parameters and returns
|
||
nothing. If there were parameters, they would go inside the parentheses, <code>()</code>.</p>
|
||
<p>Also, note that the function body is wrapped in curly brackets, <code>{}</code>. Rust
|
||
requires these around all function bodies. It’s good style to place the opening
|
||
curly bracket on the same line as the function declaration, adding one space in
|
||
between.</p>
|
||
<p>At the time of this writing, an automatic formatter tool called <code>rustfmt</code> is
|
||
under development. If you want to stick to a standard style across Rust
|
||
projects, <code>rustfmt</code> will format your code in a particular style. The Rust team
|
||
plans to eventually include this tool with the standard Rust distribution, like
|
||
<code>rustc</code>. So depending on when you read this book, it might already be installed
|
||
on your computer! Check the online documentation for more details.</p>
|
||
<p>Inside the <code>main</code> function is the following code:</p>
|
||
<pre><pre class="playpen"><code class="language-rust">
|
||
<span class="boring">#![allow(unused_variables)]
|
||
</span><span class="boring">fn main() {
|
||
</span> println!("Hello, world!");
|
||
<span class="boring">}
|
||
</span></code></pre></pre>
|
||
<p>This line does all the work in this little program: it prints text to the
|
||
screen. There are four important details to notice here. First, Rust style is
|
||
to indent with four spaces, not a tab.</p>
|
||
<p>Second, <code>println!</code> calls a Rust macro. If it called a function instead, it
|
||
would be entered as <code>println</code> (without the <code>!</code>). We’ll discuss Rust macros in
|
||
more detail in Chapter 19. For now, you just need to know that using a <code>!</code>
|
||
means that you’re calling a macro instead of a normal function.</p>
|
||
<p>Third, you see the <code>"Hello, world!"</code> string. We pass this string as an argument
|
||
to <code>println!</code>, and the string is printed to the screen.</p>
|
||
<p>Fourth, we end the line with a semicolon (<code>;</code>), which indicates that this
|
||
expression is over and the next one is ready to begin. Most lines of Rust code
|
||
end with a semicolon.</p>
|
||
<h3><a class="header" href="#compiling-and-running-are-separate-steps" id="compiling-and-running-are-separate-steps">Compiling and Running Are Separate Steps</a></h3>
|
||
<p>You’ve just run a newly created program, so let’s examine each step in the
|
||
process.</p>
|
||
<p>Before running a Rust program, you must compile it using the Rust compiler by
|
||
entering the <code>rustc</code> command and passing it the name of your source file, like
|
||
this:</p>
|
||
<pre><code class="language-text">$ rustc main.rs
|
||
</code></pre>
|
||
<p>If you have a C or C++ background, you’ll notice that this is similar to <code>gcc</code>
|
||
or <code>clang</code>. After compiling successfully, Rust outputs a binary executable.</p>
|
||
<p>On Linux, macOS, and PowerShell on Windows, you can see the executable by
|
||
entering the <code>ls</code> command in your shell. On Linux and macOS, you’ll see two
|
||
files. With PowerShell on Windows, you’ll see the same three files that you
|
||
would see using CMD.</p>
|
||
<pre><code class="language-text">$ ls
|
||
main main.rs
|
||
</code></pre>
|
||
<p>With CMD on Windows, you would enter the following:</p>
|
||
<pre><code class="language-cmd">> dir /B %= the /B option says to only show the file names =%
|
||
main.exe
|
||
main.pdb
|
||
main.rs
|
||
</code></pre>
|
||
<p>This shows the source code file with the <em>.rs</em> extension, the executable file
|
||
(<em>main.exe</em> on Windows, but <em>main</em> on all other platforms), and, when using
|
||
Windows, a file containing debugging information with the <em>.pdb</em> extension.
|
||
From here, you run the <em>main</em> or <em>main.exe</em> file, like this:</p>
|
||
<pre><code class="language-text">$ ./main # or .\main.exe on Windows
|
||
</code></pre>
|
||
<p>If <em>main.rs</em> was your “Hello, world!” program, this line would print <code>Hello, world!</code> to your terminal.</p>
|
||
<p>If you’re more familiar with a dynamic language, such as Ruby, Python, or
|
||
JavaScript, you might not be used to compiling and running a program as
|
||
separate steps. Rust is an <em>ahead-of-time compiled</em> language, meaning you can
|
||
compile a program and give the executable to someone else, and they can run it
|
||
even without having Rust installed. If you give someone a <em>.rb</em>, <em>.py</em>, or
|
||
<em>.js</em> file, they need to have a Ruby, Python, or JavaScript implementation
|
||
installed (respectively). But in those languages, you only need one command to
|
||
compile and run your program. Everything is a trade-off in language design.</p>
|
||
<p>Just compiling with <code>rustc</code> is fine for simple programs, but as your project
|
||
grows, you’ll want to manage all the options and make it easy to share your
|
||
code. Next, we’ll introduce you to the Cargo tool, which will help you write
|
||
real-world Rust programs.</p>
|
||
|
||
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|
||
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