Rust by Example: Loops

Rust has three kinds of loops: loop, while, and for.
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fn main() {

The loop keyword tells Rust to execute a block of code over and over forever, or until you explicitly tell it to stop.

 
    loop {
        println!("hello, world!");
        break;
    }

You can add the value you want returned after the break expression you use to stop the loop; that value will be returned out of the loop so you can use it.

 
    let mut counter = 0;
    let result = loop {
        counter += 1;
        if counter == 10 {
            break counter * 2;
        }
    };
    println!("The result is {}", result);

A while loop runs as long as a condition holds true.

 
    let mut number = 3;
    while number != 0 {
        println!("{}", number);
        number -= 1;
    }

A for loop is used to iterate through a collection of items.

 
    let array = [1, 2, 3, 4, 5];
    for element in array {
        println!("{} ", element);
    }

You can also use a for loop to iterate over the elements of a range, the .. is exclusive.

 
    for i in 0..5 {
        println!("{} ", i);
    }

And n use ..= is inclusive and will include the last number.

 
    for i in 0..=5 {
        println!("{}", i);
    }
}

$ rustc loops.rs
$ ./loops
hello, world!
The result is 20
3
2
1
1
2
3
4
5
0
1
2
3
4
0
1
2
3
4
5
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