Rust For Loop

In Rust, the for loop is used when you want to repeat a block of code a certain number of times or when you want to go through a sequence of items.

Basic for Loop Syntax #

The general syntax looks like this:

for variable in sequence {
    // code block
}
Code language: Rust (rust)

• variable is a name you choose that will represent each step.
• sequence tells Rust how many times to repeat the loop (later, this can be an array, a range, or other iterators).
• The { ... } block contains the code that runs each time.

Repeating an Action a Fixed Number of Times Example #

For now, let’s just simulate repeating something 3 times:

fn main() {
    for _ in 0..3 {
        println!("Hello, Rust!");
    }
}Code language: Rust (rust)

Output:

Hello, Rust!
Hello, Rust!
Hello, Rust!

Explanation:

• 0..3 is a range from 0 up to (but not including) 3.
• The _ means we don’t care about the actual number; we just want the repetition.
• This prints “Hello, Rust!” three times.

Using the Loop Variable #

If you want to know which step you are on, give the loop variable a name:

fn main() {
    for i in 0..5 {
        println!("Step number: {}", i);
    }
}Code language: Rust (rust)

This will print:

Step number: 0
Step number: 1
Step number: 2
Step number: 3
Step number: 4
Code language: Rust (rust)

break in a for Loop #

You can stop the loop early with break:

fn main() {
    for i in 0..10 {
        if i == 5 {
            println!("Stopping at {}", i);
            break;
        }
        println!("Number: {}", i);
    }
}Code language: Rust (rust)

Output will stop at 5.

continue in a for Loop #

You can skip a particular step with continue:

fn main() {
    for i in 0..6 {
        if i % 2 == 0 {
            continue; // skip even numbers
        }
        println!("Odd number: {}", i);
    }
}Code language: Rust (rust)

Only odd numbers (1, 3, 5) are printed.

Summary #

• The for loop repeats code for each item in a sequence.
• 0..n is often used to repeat code n times.
• Use break to exit early, continue to skip one step.