The type of ratios and related operations.
A ratio is the result of dividing two integers, i.e., the numerator and denominator.
use int_ratio::Ratio;
let ratio = Ratio::new(1, 3); // 1 / 3
assert_eq!(ratio.mul_trunc(20), 6); // trunc(20 * 1 / 3) = trunc(6.66..) = 6
assert_eq!(ratio.mul_round(20), 7); // round(20 * 1 / 3) = round(6.66..) = 7
println!("{:?}", ratio); // Ratio(1/3 ~= 1431655765/4294967296)