rustlings/exercises/18_iterators/iterators4.rs

44 lines
936 B
Rust

// iterators4.rs
//
// Execute `rustlings hint iterators4` or use the `hint` watch subcommand for a
// hint.
pub fn factorial(num: u64) -> u64 {
// Complete this function to return the factorial of num
// Do not use:
// - early returns (using the `return` keyword explicitly)
// Try not to use:
// - imperative style loops (for, while)
// - additional variables
// For an extra challenge, don't use:
// - recursion
// Execute `rustlings hint iterators4` for hints.
}
fn main() {
// You can optionally experiment here.
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn factorial_of_0() {
assert_eq!(1, factorial(0));
}
#[test]
fn factorial_of_1() {
assert_eq!(1, factorial(1));
}
#[test]
fn factorial_of_2() {
assert_eq!(2, factorial(2));
}
#[test]
fn factorial_of_4() {
assert_eq!(24, factorial(4));
}
}