1. In the src/bin folder, create a file called variadic.rs

2. Add the following code and run it with cargo run --bin variadic:

1   macro_rules! multiply {
2     // Edge case
3     ( $last:expr ) => { $last };
4
5     ( $head:expr, $($tail:expr), +) => {
6       // Recursive call
7       $head * multiply!($($tail),+)
8     };
9   }
10
11  fn main() {
12    // You can call multiply! with
13    // as many parameters as you want
14    let val = multiply!(2, 4, 8);
15    println!("2*4*8 = {}", val)
16  }