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/*
Copyright 2024-2025 Owain Davies
SPDX-License-Identifier: Apache-2.0 OR MIT
*/
use crate::Arbi;
impl Arbi {
/// Return `true` if this integer is odd, `false` otherwise.
///
/// # Examples
/// ```
/// use arbi::Arbi;
/// let zero = Arbi::zero();
/// assert!(!zero.is_odd());
/// let a = Arbi::from(-123456789);
/// assert!(a.is_odd());
/// let b = Arbi::from(-12345678);
/// assert!(!b.is_odd());
/// ```
///
/// # Complexity
/// \\( O(1) \\)
#[inline(always)]
pub fn is_odd(&self) -> bool {
if self.size() == 0 {
false
} else {
(self.vec[0] & 1) != 0
}
}
/// Return `true` if this integer is even, `false` otherwise.
///
/// # Examples
/// ```
/// use arbi::Arbi;
///
/// let zero = Arbi::zero();
/// assert!(zero.is_even());
/// let a = Arbi::from(-12345678);
/// assert!(a.is_even());
/// let b = Arbi::from(-123456789);
/// assert!(!b.is_even());
/// ```
///
/// # Complexity
/// \\( O(1) \\)
#[inline(always)]
pub fn is_even(&self) -> bool {
!self.is_odd()
}
}
#[cfg(test)]
mod tests {
use crate::{Arbi, DDigit, Digit, SDDigit};
#[test]
fn test_even_or_odd() {
let mut arbi: Arbi;
arbi = Arbi::zero();
assert!(arbi.is_even());
assert!(!arbi.is_odd());
arbi = Arbi::from(Digit::MAX);
assert!(arbi.is_odd());
assert!(!arbi.is_even());
arbi = Arbi::from(Digit::MAX as DDigit + 1);
assert!(arbi.is_even());
assert!(!arbi.is_odd());
arbi = Arbi::from(-(Digit::MAX as SDDigit));
assert!(arbi.is_odd());
assert!(!arbi.is_even());
arbi -= 1;
assert!(arbi.is_even());
assert!(!arbi.is_odd());
}
}