Rust from Zero

Before we go too deep, should be good if we understand the basic thing about Rust. As you know, I have a background in other programming Languages (dart, Kotlin, etc). So the Rust from Zero it's not from those who never or don't have experience in programming. I make this series to write my progress and also about my understanding when learning a new programming language, especially Rust.

File naming

In Rust files always end with .rs extension. If you are using more than one word in your file name, you can use _ (underscore) to separate them.

👍🏻 Do

hello.rs
hello_word.rs

🙅🏻‍♂️ Don't

Hello.rs
HelloWord.rs
helloWord.rs

Create new project

In Rust, we have two options to create the project.

Without Cargo

mkdir project_name
cd project_name
touch main.rs // create the file main.rs

So, if we want to create a Rust project without Cargo, we need to create the file and folder manually the first time. But if

With Cargo

cargo new project_name

We just run that command, cargo will generate automatically the base project with Cargo support, which is Cargo work as Package Manager in Rust

Write, Compile, and Run a Rust Program

In the main.rs if you create your project with Cargo, you can open and see the file inside src/main.rs should be like this.

fn main(){
	println!("Hello, LazycatLabs!");
}

but if you create it manually you can copy and paste that code into your main.rs. And after that, we need to compile the file first

$ rustc main.rs

after you run that command, if you're on Linux, MacOS or PowerShell on Windows you will see the executable file

$ ls
main main.rs

But when you are using CMD on Windows, you also will see main.exe and main.pdb. And then you can run your Rust Program with type this on your terminal.

$ ./main # or .\main.exe on Windows

Anatomy of a Rust Program

Let's review the main.rs program in detail.

fn main() {

}

These lines define a function fn named main. The main function is special because it's always the first code that run in every executable Rust program. In that code has no parameter and return nothing. If we want to add parameter, that parameter should be inside parentheses ().

The function body is wrapped in {}. Rust requires curly brackets around all function bodies. You can use an automatic formatter tool called rustfmt to format your code. And if you're use IntelliJ Idea and install Rust plugin you can format your code easily and also you can add an external tool to analysis your code

The body of the main function holds the following code:

println!("Hello, Lazycatlabs!");

There are 4 important details to notice here.

Rust style is to indent with four spaces, not a tab
println! calls a Rust macro, I can explain it later because I need to the Caphter 19 to understand it 😅
You see the "Hello, Lazycatlabs!" string, We pass the string as argument to println! and the string is printed to the screen.
We end the line with semicolon (;) which is indicates that this expression is over.

Cargo

Cargo is Rust's build system and package manager. Cargo also can build build your code, downloading the libraries your code depends on and build that library.

When you create your project using Cargo like this

cargo new project_name

That's automatically generate the folder project.

.
├── Cargo.lock
├── Cargo.toml
└─── src
     └── main.rs

And when you open the Cargo.toml file, you should see this code

[package]
name = "rust_from_zero"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
rand = "0.8.5"

You can define what library do you want to use below [dependecies] for that example I want to use rand library with version 0.8.5.

In [package] you will see the default information generated based on your project name, and you can see here for more keys and their definition in here.

(β)Log

Rust from Zero - 001