Enum RoundingMode 

pub enum RoundingMode {
    Down,
    Up,
    TowardZero,
    AwayFromZero,
    HalfUp,
    HalfDown,
    HalfEven,
}

Rounding mode selector (7 modes per IEEE 754-2008).

Variants

Down

Round toward negative infinity (floor).

-1.5 → -2, 1.5 → 1

Up

Round toward positive infinity (ceiling).

-1.5 → -1, 1.5 → 2

TowardZero

Round toward zero (truncate).

-1.9 → -1, 1.9 → 1

AwayFromZero

Round away from zero.

-1.1 → -2, 1.1 → 2

HalfUp

Round half toward positive infinity (“school” rounding).

0.5 → 1, -0.5 → 0

HalfDown

Round half toward negative infinity.

0.5 → 0, -0.5 → -1

HalfEven

Round half to nearest even digit (banker’s rounding) — default.

0.5 → 0, 1.5 → 2, 2.5 → 2, 3.5 → 4

Chosen as default because it is statistically unbiased across large numbers of operations — critical for interest accrual and index updates.

Trait Implementations

impl Clone for RoundingMode

fn clone(&self) -> RoundingMode

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for RoundingMode

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for RoundingMode

fn default() -> RoundingMode

Returns the “default value” for a type.

impl Hash for RoundingMode

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for RoundingMode

fn eq(&self, other: &RoundingMode) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for RoundingMode

impl Eq for RoundingMode

impl StructuralPartialEq for RoundingMode