iterators4.rs (881B)
1 fn factorial(num: u64) -> u64 { 2 // TODO: Complete this function to return the factorial of `num` which is 3 // defined as `1 * 2 * 3 * … * num`. 4 // https://en.wikipedia.org/wiki/Factorial 5 // 6 // Do not use: 7 // - early returns (using the `return` keyword explicitly) 8 // Try not to use: 9 // - imperative style loops (for/while) 10 // - additional variables 11 // For an extra challenge, don't use: 12 // - recursion 13 } 14 15 fn main() { 16 // You can optionally experiment here. 17 } 18 19 #[cfg(test)] 20 mod tests { 21 use super::*; 22 23 #[test] 24 fn factorial_of_0() { 25 assert_eq!(factorial(0), 1); 26 } 27 28 #[test] 29 fn factorial_of_1() { 30 assert_eq!(factorial(1), 1); 31 } 32 #[test] 33 fn factorial_of_2() { 34 assert_eq!(factorial(2), 2); 35 } 36 37 #[test] 38 fn factorial_of_4() { 39 assert_eq!(factorial(4), 24); 40 } 41 }