rust nesting and labels loop

Rust Nesting and Labels in Loops

In Rust, nesting and labels can be used in loops to control the flow of execution. Nesting refers to having one loop inside another loop, and labels are used to identify specific loops and control their behavior.

To nest loops in Rust, you can simply place one loop inside another. This allows you to iterate over multiple levels of data or perform complex iterations. Here's an example of nesting loops in Rust:

fn main() {
    for i in 1..=3 {
        for j in 1..=3 {
            println!("i: {}, j: {}", i, j);
        }
    }
}

In this example, we have an outer loop that iterates over the values 1 to 3, and an inner loop that also iterates over the values 1 to 3. The println! statement is executed for each combination of i and j, resulting in the following output:

i: 1, j: 1
i: 1, j: 2
i: 1, j: 3
i: 2, j: 1
i: 2, j: 2
i: 2, j: 3
i: 3, j: 1
i: 3, j: 2
i: 3, j: 3

Labels in Rust are used to identify loops and control their behavior. They are defined by prefixing an identifier followed by a colon (:) before the loop. Here's an example of using labels in loops:

fn main() {
    'outer: for i in 1..=3 {
        'inner: for j in 1..=3 {
            if i == 2 && j == 2 {
                break 'outer;
            }
            println!("i: {}, j: {}", i, j);
        }
    }
}

In this example, we have an outer loop labeled 'outer and an inner loop labeled 'inner. When the condition i == 2 && j == 2 is met, the break 'outer statement is executed, causing the program to break out of the outer loop. As a result, the output is:

i: 1, j: 1
i: 1, j: 2
i: 1, j: 3

Note that labels are not required for nesting loops, but they can be useful when you want to break out of a specific loop from within a nested loop.

I hope this explanation helps! Let me know if you have any further questions.