Double: decimal points are fun

Syntax:// implicit Double constant

let x = floating-point_number

// implicit Double variable

var y = floating-point_number

// explicit Double constant

let x: Double = floating-point_number

// explicit Double variable

var y: Double = floating-point_number

A Double is a 64-bit floating-point number that has a precision of at least 15 decimal digits. A floating-point number is a number with a fractional component and can be written in many different ways in Swift. When declaring variables or constants with a value of a floating-point, Swift always chooses Double if the type is not specified as Float.

let x = 123.45 * // declare a constant as an implicit Double*

var y = 1.2345e2 * // declare a variable as an implicit Double using an explonent *

var z = 0x7B.73333p0 * // declare a variable as an implicit Double using hexadecimal (123.45 decimal) *

var abc = 5 + y * // Swift chooses that abc will be a Double since it is a combination of a whole number // and a floating-point number*

var a,b,c : Double