match n { // Pattern match
 0 => 1,
 1 => 1,
 _ => fib(n - 1) + fib(n - 2), // Recursive call
 } // not need `return`
 }
 
 fn main() {
 let fib5 = fib(5); // local variable (Immutable is default)
 println!("fib(5): {}", fib5); // `{}` is placeholder
 // => 8
 }