AdditiveArithmetic

The AdditiveArithmetic protocol provides a suitable basis for additive arithmetic on scalar values, such as integers and floating-point numbers, or vectors. You can write generic methods that operate on any numeric type in the standard library by using the AdditiveArithmetic protocol as a generic constraint.

The following code declares a method that calculates the total of any sequence with AdditiveArithmetic elements.

extension Sequence where Element: AdditiveArithmetic {
    func sum() -> Element {
        return reduce(.zero, +)
    }
}

The sum() method is now available on any sequence with values that conform to AdditiveArithmetic, whether it is an array of Double or a range of Int.

let arraySum = [1.1, 2.2, 3.3, 4.4, 5.5].sum()
// arraySum == 16.5

let rangeSum = (1..<10).sum()
// rangeSum == 45

To add AdditiveArithmetic protocol conformance to your own custom type, implement the required operators, and provide a static zero property using a type that can represent the magnitude of any value of your custom type.