...

This command will create an executable in target/release instead of target/debug. The optimizations make your Rust code run faster, but turning them on lengthens the time it takes for your program to compile. This is why there are two different profiles: one for development, when you want to rebuild quickly and often, and another for building the final program you’ll give to a user that won’t be rebuilt repeatedly and that will run as fast as possible. If you’re benchmarking your code’s running time, be sure to run cargo build --release and benchmark with the executable in target/release.

Naming Conventions

Rust code uses snake case as the conventional style for function and variable names, in which all letters are lowercase and underscores separate words.

Constants are all uppercase.

const PI: f32 = 3.14;

fn main() {
	let my_var = 5;
    another_function(my_var);
}

fn another_function(x: i32) {
    println!("The value of x is: {x}");
} 

Variables

Immutable/Mutable

...

fn main() {
	let months = ["January", "February", "March", "April", "May", "June", "July",
              "August", "September", "October", "November", "December"];

	let a: [i32; 5] = [1, 2, 3, 4, 5];

	//access values

	let first = a[0];
	let second = a[1];
}

Functions

Rust code uses snake case as the conventional style for function and variable names, in which all letters are lowercase and underscores separate words

fn main() {
    another_function(5);
}

fn another_function(x: i32) {
    println!("The value of x is: {x}");
}

Returning Values

fn main() {
    let x = plus_one(5);

    println!("The value of x is: {x}");
}

fn plus_one(x: i32) -> i32 {
    x + 1
}

The value returned from function plus_one is the value of x+1 or 6. Notice that there is no semi-colon at the end of the line. This is an expression.

Comments

Rust uses two forward slashes ( // ) to indicate a comment. 

For comments that extend beyond a single line, you’ll need to include // on each line.

Comments can also be placed at the end of lines containing code

// So we’re doing something complicated here, long enough that we need
// multiple lines of comments to do it! Whew! Hopefully, this comment will
// explain what’s going on.

fn main() {
    let lucky_number = 7; // I’m feeling lucky today
}

Control Flow

If Expression

fn main() {
    let number = 6;

    if number % 4 == 0 {
        println!("number is divisible by 4");
    } else if number % 3 == 0 {
        println!("number is divisible by 3");
    } else if number % 2 == 0 {
        println!("number is divisible by 2");
    } else {
        println!("number is not divisible by 4, 3, or 2");
    }
}

Using if in a let Statement

fn main() {
    let condition = true;
    let number = if condition { 5 } else { 6 };

    println!("The value of number is: {number}");
}

Loops

fn main() {
    let mut counter = 0;

    let result = loop {
        counter += 1;

        if counter == 10 {
            break counter * 2;
        }
    };

    println!("The result is {result}");
}

While Loop

fn main() {
    let mut number = 3;

    while number != 0 {
        println!("{number}!");

        number -= 1;
    }

    println!("LIFTOFF!!!");
}

IntelliJ IDE

To use Rust in IntelliJ install the following plugins:

...