**Course Title:** Mastering Rust: From Basics to Systems Programming **Section Title:** Control Flow and Functions **Topic:** Looping constructs: loop, while, and for ### Introduction to Looping Constructs In the previous topic, we explored conditional statements in Rust, which allow us to execute different blocks of code based on certain conditions. Now, we'll delve into looping constructs, which enable us to execute a block of code repeatedly until a specific condition is met. This topic will cover the three primary looping constructs in Rust: `loop`, `while`, and `for`. ### Looping with `loop` The `loop` keyword in Rust is used to create an infinite loop that runs until it encounters a `break` statement. Here's a basic example of a `loop`: ```rust fn main() { let mut i = 0; loop { println!("Loop iteration: {}", i); i += 1; if i >= 5 { break; } } } ``` In this example, the `loop` will continue to print "Loop iteration: <i>" until `i` reaches 5. **Note:** You can also use the `return` keyword to exit the loop. ### Looping with `while` The `while` loop is used to execute a block of code as long as a specific condition is true. Here's an example of a `while` loop: ```rust fn main() { let mut i = 0; while i < 5 { println!("While iteration: {}", i); i += 1; } } ``` In this example, the `while` loop will continue to print "While iteration: <i>" as long as `i` is less than 5. ### Looping with `for` The `for` loop is used to iterate over a sequence of values, such as an array, vector, or range. Here's an example of a `for` loop: ```rust fn main() { let numbers = [1, 2, 3, 4, 5]; for i in numbers { println!("For iteration: {}", i); } } ``` In this example, the `for` loop will iterate over the `numbers` array and print each value. **Note:** You can also use the `..` syntax to create a range, like this: ```rust fn main() { for i in 1..5 { println!("For iteration: {}", i); } } ``` This will iterate over the range of numbers from 1 to 4. ### Key Concepts * The `loop` keyword is used to create an infinite loop that runs until it encounters a `break` statement. * The `while` loop is used to execute a block of code as long as a specific condition is true. * The `for` loop is used to iterate over a sequence of values, such as an array, vector, or range. ### Practical Takeaways * Use `loop` when you need to execute a block of code an unknown number of times. * Use `while` when you need to execute a block of code as long as a specific condition is true. * Use `for` when you need to iterate over a sequence of values. ### Conclusion In this topic, we explored the three primary looping constructs in Rust: `loop`, `while`, and `for`. We learned how to use each loop type to execute a block of code repeatedly, and we discussed key concepts and practical takeaways to help you apply these concepts in your own Rust programs. **Further Reading** * [The Rust Programming Language Book: Loops](https://doc.rust-lang.org/book/ch03-05-control-flow.html#loops) * [Rust Documentation: Loops](https://doc.rust-lang.org/std/iter/trait.Iterator.html#definition) **What's Next?** In the next topic, we'll cover defining and using functions, including function arguments and return types. **Do you have any questions or need help with a specific topic? Please leave a comment below!**