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use std::io::prelude::*;
use std::fmt::{Display, Formatter, Result};
use Value::*;
#[derive(Eq, PartialEq, Copy, Clone, Debug, Hash)]
pub enum Value {
Fizz,
Buzz,
FizzBuzz,
Number(u32),
}
impl From<u32> for Value {
fn from(n: u32) -> Value {
match (n % 3, n % 5) {
(0, 0) => FizzBuzz,
(0, _) => Fizz,
(_, 0) => Buzz,
(_, _) => Number(n),
}
}
}
impl Display for Value {
fn fmt(&self, f: &mut Formatter) -> Result {
match *self {
Fizz => write!(f, "Fizz"),
Buzz => write!(f, "Buzz"),
FizzBuzz => write!(f, "FizzBuzz"),
Number(n) => write!(f, "{}", n),
}
}
}
pub fn fizzbuzz<I>(it: I)
where
I: Iterator<Item = u32>,
{
let stdout = std::io::stdout();
let mut stdout = stdout.lock();
for n in it {
writeln!(stdout, "{}", Value::from(n)).expect("Failed to output");
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test() {
let expected = [
FizzBuzz,
Number(1),
Number(2),
Fizz,
Number(4),
Buzz,
Fizz,
Number(7),
Number(8),
Fizz,
Buzz,
Number(11),
Fizz,
Number(13),
Number(14),
FizzBuzz,
Number(16),
Number(17),
Fizz,
Number(19),
];
for (i, &exp) in expected.iter().enumerate() {
assert_eq!(Value::from(i as u32), exp);
}
}
}