AiViewz: Create and Share Your Content

Objective

Loops and If-else statements

By the end of this lesson, you will understand how to implement control flow in Rust using if statements, loop, while, and for loops. You will learn how to make decisions in your code and iterate over collections.

1. If Statements

if statements allow you to execute code based on a condition. Rust's if statements can be used in a variety of ways, including with else and else if for additional conditions.

Basic If Statement:

let number = 10;

if number < 5 {
    println!("The number is less than 5.");
} else {
    println!("The number is 5 or greater.");
}

If with Else If:

let number = 10;

if number < 5 {
    println!("The number is less than 5.");
} else if number < 15 {
    println!("The number is between 5 and 15.");
} else {
    println!("The number is 15 or greater.");
}

Returning a Value from If: In Rust, if statements can also return values. This can be useful for assigning values based on conditions.

let number = 10;
let result = if number < 5 { "Less than 5" } else { "5 or more" };
println!("Result: {}", result);

2. Loops

Rust provides several ways to create loops: loop, while, and for. Each serves a different purpose.

Infinite Loop with Loop: The loop construct creates an infinite loop unless explicitly exited with a break statement.

let mut count = 0;

loop {
    if count >= 5 {
        break; // Exit the loop when count reaches 5
    }
    println!("Count: {}", count);
    count += 1;
}

While Loop: The while loop continues executing as long as the given condition evaluates to true.

let mut count = 0;

while count < 5 {
    println!("Count: {}", count);
    count += 1;
}

For Loop: The for loop is used to iterate over collections, such as arrays or ranges. It is often the preferred loop in Rust due to its safety and expressiveness.

Iterating Over a Range:

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

Iterating Over an Array: You can also use a for loop to iterate through an array or a vector.

let numbers = [1, 2, 3, 4, 5];

for number in numbers.iter() {
    println!("Number: {}", number);
}

3. Match Statement

In addition to if statements, Rust offers a powerful match statement for pattern matching, which can often serve as a more elegant alternative to multiple if statements.

Basic Match:

let number = 3;

match number {
    1 => println!("One"),
    2 => println!("Two"),
    3 => println!("Three"),
    _ => println!("Other"), // _ acts as a default case
}

4. Conclusion

In this lesson, you learned about control flow in Rust, focusing on if statements and loops. You explored how to make decisions in your code and iterate over collections using loop, while, and for. You also got a glimpse of the match statement for pattern matching, providing more flexibility in handling multiple conditions.