Rust syntax: Difference between revisions

Revision as of 16:05, 18 July 2025

Revision as of 13:32, 12 August 2025

Line 87:

<syntaxhighlight lang="rust">

fn main() {

let foo: i32 = 10;

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

}

Line 97:

fn main() {

// This code would not compile without adding "mut".

let mut foo: i32 = 10;

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

foo = 20;

Line 108:

<syntaxhighlight lang="rust">

fn main() {

let foo: i32 = 10;

// This will output "The value of foo is 10"

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

let foo: i32 = foo * 2;

// This will output "The value of foo is 20"

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

Line 121:

<syntaxhighlight lang="rust">

fn main() {

let letters: str = "abc";

let letters: usize = letters.len();

}

</syntaxhighlight>

Line 132:

<syntaxhighlight lang="rust">

fn main() {

let x: i32 = {

println!("this is inside the block");

1 + 2

Line 154:

<syntaxhighlight lang="rust">

fn main() {

let x: i32 = 10;

if x > 5 {

println!("value is greater than five");

Line 173:

<syntaxhighlight lang="rust">

fn main() {

let x: i32 = 10;

let new_x: i32 = if x % 2 == 0 { x / 2 } else { 3 * x + 1 };

println!("{new_x}");

}

Line 185:

fn main() {

// Iterate over all integers from 4 to 10

let mut value: i32 = 4;

while value <= 10 {

println!("value = {value}");

Line 222:

<syntaxhighlight lang="rust">

fn main() {

let value: i32 = 456;

let mut x: i32 = 1;

let y = loop {

x *= 10;

Line 232:

println!("largest power of ten that is smaller than or equal to value: {y}");

let mut up: i32 = 1;

'outer: loop {

let mut down: i32 = 120;

loop {

if up > 100 {

Line 296:

let tuple: (u32, i64) = (3, -3);

let array: [i8; 5] = [1, 2, 3, 4, 5];

let tuplevalue: (bool, bool) = (true,tuple.1; true);// -3

let value: i8 = tuple.1array[2]; // -3

let value = array[2]; // 3

</syntaxhighlight>

Line 318 ⟶ 317:

fn main() {

let s: String = String::from("Hello, World");

print_string(s); // s consumed by print_string

// s has been moved, so cannot be used any more

Line 333 ⟶ 332:

fn main() {

let s: String = String::from("Hello, World");

print_string(&s); // s borrowed by print_string

print_string(&s); // s has not been consumed; we can call the function many times

Line 352 ⟶ 351:

<syntaxhighlight lang="rust">

fn main() {

let x: i32 = 5; // ------------------+- Lifetime 'a

// |

let r: &i32 = &x; // -+-- Lifetime 'b |

// | |

println!("r: {}", r); // | |

Line 366 ⟶ 365:

<syntaxhighlight lang="rust">

fn main() {

let r: &i32; // ------------------+- Lifetime 'a

// |

{ // |

let x: i32 = 5; // -+-- Lifetime 'b |

r = &x; // ERROR: x does | |

} // not live long -| |

Line 707 ⟶ 706:

fn main() {

let x: i32 = sum!(1, 2, 3);

println!("{x}"); // prints 6

}