“You can access the minimum and maximum values of each integer type with its min and max properties:
let minValue = UInt8.min // minValue is equal to 0, and is of type UInt8
let maxValue = UInt8.max // maxValue is equal to 255, and is of type UInt8
The values of these properties are of the appropriate-sized number type (such as UInt8 in the example above) and can therefore be used in expressions alongside other values of the same type.”
Excerpt From: Apple Inc. “The Swift Programming Language.” iBooks. https://itun.es/in/jEUH0.