Day 4: Control Flow

Control flow determines the order of execution. Rust has powerful pattern matching!

What You'll Learn

• if/else expressions
• The match expression
• Loops: loop, while, for

If/Else as Expressions

In Rust, if is an expression that returns a value:

let number = if condition { 5 } else { 10 };

Match Expressions

match is Rust's powerful pattern matching:

match value {
    1 => println!("one"),
    2 | 3 => println!("two or three"),
    4..=10 => println!("four to ten"),
    _ => println!("something else"),  // catch-all
}

The Task: FizzBuzz

Implement the classic FizzBuzz for a single number:

• Return "FizzBuzz" if divisible by both 3 and 5
• Return "Fizz" if divisible by 3 only
• Return "Buzz" if divisible by 5 only
• Return the number as a string otherwise

Requirements

• Check divisibility with the modulo operator %
• Return a String
• Test case: fizzbuzz(15) → "FizzBuzz"

Hints

• Use n % 3 == 0 to check divisibility
• Check both 3 AND 5 first!
• Use n.to_string() to convert number to String
• Use String::from("...") for string literals