Decimal class abstract

Decimal number.

Why?

Decimal numbers enable avoiding numerical issues with double. For example, CurrencyAmount uses Decimal to prevent numerical errors causing wrong prices.

Things to know

Internally decimal numbers are represented as a fraction of two integers nominator / denominator, where denominator is some power of 10 (1, 10, 100, 1000, etc.).

You need to define the number of decimal digits you need. This is possible with the method usingFractionDigits. Operations will return decimal numbers with N fraction digits, where N is the highest number of fraction digits in the arguments.

For example:

import package:kind/kind.dart';

void main() {
  // Declare 1 and 3.
  final one = Decimal('1.00'); // <-- 2 digits
  final three = Decimal('3').usingFractionDigits(5); // <-- 5 digits

  // Calculate 1/3 with 5 digits after dot.
  print(one / three);
  // --> 3.33333
}
Implemented types

Constructors

Decimal(String s)
Constructs a decimal number from a string ("3.14").
factory
Decimal.fromDouble(num value, {required int fractionDigits})
Constructs a decimal number from double.
const
factory

Properties

denominator → int
Denominator (parameter b in a/b).
no setter
fractionDigits → int
Number of digits after dot (".").
no setter
hashCode → int
The hash code for this object.
no setteroverride
isNegative → bool
Whether the value is negative.
no setter
nominator → int
Nominator (parameter a in a/b).
no setter
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

ceil() → int
Calculates the lowest integer greater than or equal to this.
clamp(Decimal min, Decimal max) → Decimal
compareTo(Decimal other) → int
Compares this object to another object.
override
floor() → int
Calculates the highest integer less than or equal to this.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
round() → int
Rounds the decimal number.
scale(num value) → Decimal
toDouble() → double
Returns this as a floating-point value.
toInt() → int
Returns floor().
toString() → String
A string representation of this object.
override
usingFractionDigits(int fractionDigits) → Decimal

Operators

operator *(Decimal other) → Decimal
Calculates product of this and the argument.
operator +(Decimal other) → Decimal
Calculates sum of this and the argument.
operator -(Decimal other) → Decimal
Calculates difference of this and the argument.
operator /(Decimal other) → Decimal
Calculates fraction of this and the argument.
operator <(Decimal other) → bool
operator <=(Decimal other) → bool
operator ==(Object other) → bool
The equality operator.
override
operator >(Decimal other) → bool
operator >=(Decimal other) → bool
operator unary-() → Decimal
Negates the decimal number.

Static Methods

tryParse(String s) → Decimal?
Parses decimal number.

Constants

one → const Decimal
Value Decimal('1').
two → const Decimal
Value Decimal('2').
zero → const Decimal
Value Decimal('0').