malachite_q/conversion/
is_integer.rs

1// Copyright © 2025 Mikhail Hogrefe
2//
3// This file is part of Malachite.
4//
5// Malachite is free software: you can redistribute it and/or modify it under the terms of the GNU
6// Lesser General Public License (LGPL) as published by the Free Software Foundation; either version
7// 3 of the License, or (at your option) any later version. See <https://www.gnu.org/licenses/>.
8
9use crate::Rational;
10use malachite_base::num::conversion::traits::IsInteger;
11
12impl IsInteger for &Rational {
13    /// Determines whether a [`Rational`] is an integer.
14    ///
15    /// $f(x) = x \in \Z$.
16    ///
17    /// # Worst-case complexity
18    /// Constant time and additional memory.
19    ///
20    /// # Examples
21    /// ```
22    /// use malachite_base::num::basic::traits::{One, Zero};
23    /// use malachite_base::num::conversion::traits::IsInteger;
24    /// use malachite_q::Rational;
25    ///
26    /// assert_eq!(Rational::ZERO.is_integer(), true);
27    /// assert_eq!(Rational::ONE.is_integer(), true);
28    /// assert_eq!(Rational::from(100).is_integer(), true);
29    /// assert_eq!(Rational::from(-100).is_integer(), true);
30    /// assert_eq!(Rational::from_signeds(22, 7).is_integer(), false);
31    /// assert_eq!(Rational::from_signeds(-22, 7).is_integer(), false);
32    /// ```
33    #[inline]
34    fn is_integer(self) -> bool {
35        self.denominator == 1u32
36    }
37}