1 use trace_var::trace_var; 2 main()3 fn main() { 4 println!("{}", factorial(8)); 5 } 6 7 #[trace_var(p, n)] factorial(mut n: u64) -> u648 fn factorial(mut n: u64) -> u64 { 9 let mut p = 1; 10 while n > 1 { 11 p *= n; 12 n -= 1; 13 } 14 p 15 } 16