#![allow(dead_code, deprecated, unused_variables, unused_mut)]
#![feature(core_float_math)]
use core::f64;
fn main() {
    let positive = 4.0_f64;
    let negative = -4.0_f64;
    let negative_zero = -0.0_f64;
    assert_eq!(f64::math::sqrt(positive), 2.0);
    assert!(f64::math::sqrt(negative).is_nan());
    assert_eq!(f64::math::sqrt(negative_zero), negative_zero);
}