Rust by Example

let mut counter = 0;

let result = loop {

counter += 1;

if counter == 10 {

break counter * 2;

}

};

assert_eq!(result, 20);

}

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while

The while keyword can be used to run a loop while a condition is true.

Let's write the infamous FizzBuzz using a while loop.

fn main() {

// A counter variable

let mut n = 1;

// Loop while `n` is less than 101

while n < 101 {

if n % 15 == 0 {

println!("fizzbuzz");

} else if n % 3 == 0 {

println!("fizz");

} else if n % 5 == 0 {

println!("buzz");

} else {

println!("{}", n);

}

// Increment counter

n += 1;

}

}

הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה

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for loops

for and range

The for in construct can be used to iterate through an Iterator. One of the easiest ways to create an iterator is to use the range notation a..b. This yields values from a (inclusive) to b (exclusive) in steps of one.

Let's write FizzBuzz using for instead of while.

fn main() {

// `n` will take the values: 1, 2, ..., 100 in each iteration

for n in 1..101 {

if n % 15 == 0 {

println!("fizzbuzz");

} else if n % 3 == 0 {

println!("fizz");

} else if n % 5 == 0 {

println!("buzz");

} else {

println!("{}", n);

}

}

}

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Alternatively, a..=b can be used for a range that is inclusive on both ends. The above can be written as:

fn main() {

// `n` will take the values: 1, 2, ..., 100 in each iteration