Rust For Loop Statement

Rust Programming

The for loop in Rust is used to iterate a range of numbers. The syntax of for loop is:

for variable in lower_bound_number..upper_bound_number {

    // code block

}{codeBox}

Let's take a look at an example,

Example: Rust for Loop

fn main() {

    // usage of for loop

    for i in 1..6 {

        println!("{}", i);

    }

}{codeBox}

Output

1

2

3

4

5{codeBox}

In this example, we print numbers 1 to 5 using the for syntax. If we look at the example closely, we see

for i in 1..6 {

    println!("{}", i);

}{codeBox}

Here,

• for - is the keyword to start any for loop
• i - is known as the loop variable and should be a valid variable name
• in - is the keyword used to iterate over a series of values with for
• 1..6 - is known as an Iterator where 1 is the lower bound and 6 is the upper bound. This yields values from 1 (inclusive) to 6 (exclusive) in steps of one.

Example: Sum of First 10 Natural Numbers using for Loop

fn main() {

    let mut sum = 0;

    

    // for loop to iterate over first 10 natural numbers

    for i in 1..11 {

        sum += i;

    }

    println!("Sum: {}", sum);

}{codeBox}

Output

Sum: 55{codeBox}

Here, we loop over the iterator 1..11, which yields values from 1 to 10. A sum variable is created to sum all the values in each iteration. Finally, we print the sum of all the values.

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