#![allow(dead_code, deprecated, unused_variables, unused_mut)]
#![feature(core_float_math)]
use core::f64;
fn main() {
    let x = 2.0_f64;
    let abs_difference = (f64::math::powi(x, 2) - (x * x)).abs();
    assert!(abs_difference <= 1e-6);
    assert_eq!(f64::math::powi(f64::NAN, 0), 1.0);
}