Aller au contenu

Bases

Hello world

1
2
3
4
5
fn main() {
    // Our main function does one task: show a message
    // println! displays the input "Hello, world!" to the screen
    println!("Hello, world!");
}

Substitution

1
2
3
4
fn main() {
    // Call println! with three arguments: a string, a value, a value
    println!("The first letter of the English alphabet is {} and the last letter is {}.", 'A', 'Z');
}

Variables

Immuable:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
// Declare a variable
let a_number;

// Declare a second variable and bind the value
let a_word = "Ten";

// Bind a value to the first variable
a_number = 10;

println!("The number is {}.", a_number);
println!("The word is {}.", a_word);

Mutable:

1
2
3
4
5
6
7
// The `mut` keyword lets the variable be changed
let mut a_number = 10; 
println!("The number is {}.", a_number);

// Change the value of an immutable variable
a_number = 15;
println!("Now the number is {}.", a_number);

Mise en mémoire fantôme:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
// Declare first variable binding with name "shadow_num"
let shadow_num = 5;

// Declare second variable binding, shadows existing variable "shadow_num" 
let shadow_num = shadow_num + 5; 

// Declare third variable binding, shadows second binding of variable "shadow_num"
let shadow_num = shadow_num * 2; 

println!("The number is {}.", shadow_num);

Typer une variable

1
2
let number: u32 = 14;
println!("The number is {}.", number);

Tuple

1
2
3
4
5
// Declare a tuple of three elements
let tuple_e = ('E', 5i32, true);

// Use tuple indexing and show the values of the elements in the tuple
println!("Is '{}' the {}th letter of the alphabet? {}", tuple_e.0, tuple_e.1, tuple_e.2);

Struct

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
// Instantiate classic struct, specify fields in random order, or in specified order
let user_1 = Student { name: String::from("Constance Sharma"), remote: true, level: 2 };
let user_2 = Student { name: String::from("Dyson Tan"), level: 5, remote: false };

// Instantiate tuple structs, pass values in same order as types defined
let mark_1 = Grades('A', 'A', 'B', 'A', 3.75);
let mark_2 = Grades('B', 'A', 'A', 'C', 3.25);

println!("{}, level {}. Remote: {}. Grades: {}, {}, {}, {}. Average: {}", user_1.name, user_1.level, user_1.remote, mark_1.0, mark_1.1, mark_1.2, mark_1.3, mark_1.4);

println!("{}, level {}. Remote: {}. Grades: {}, {}, {}, {}. Average: {}", user_2.name, user_2.level, user_2.remote, mark_2.0, mark_2.1, mark_2.2, mark_2.3, mark_2.4);