Rust Notes 4

Range

Rather than using C style loop, in Rust, we use ..= to indicate a range:

for i in 1..=5 {
    println!("{}",i);
}

Output:

1
2
3
4
5

Sequences are only allowed for numeric or character types because they can be consecutive.

for i in 'a'..='z' {
    println!("{}",i);
}

Char

Use '' . "" is for the string

fn main() {
    let c = 'z';
    let z = 'ℤ';
    let cat= '😻';
}

Accept Unicode, occupy 4 bytes.

Bool

Only 1 byte.

fn main() {
    let t = true;
    let f: bool = false;
}

Unit type

Literally, it is ().

Yes, the unit type is (), and the value of this type is also, and only ().

It’s similar to void in other languages.

Sometimes, you may come across code like Result<(), String>. This is an example of generic types in Rust. If you’re familiar with C++ generic types, you can figure out that we pass 2 types into the Result, regardless of what the Result actually is.