cheat.sheets/sheets/_swift/types

// Swift 4 builtin data types:
//
// * Int or UInt (Int32, Int64, UInt32, UInt64)
// * Float
// * Double
// * Bool
// * String
// * Character
// * Optional − a variable that can hold either a value or no value.
// * Tuples
//
// +--------+-------------------+--------------------------------------------+
// | Type   | Typical Bit Width | Typical Range                              |
// | -------|-------------------|--------------------------------------------+
// | Int8   | 1byte             | -127 to 127                                |
// | UInt8  | 1byte             | 0 to 255                                   |
// | Int32  | 4bytes            | -2147483648 to 2147483647                  |
// | UInt32 | 4bytes            | 0 to 4294967295                            |
// | Int64  | 8bytes            | -9223372036854775808 to 9223372036854775807|
// | UInt64 | 8bytes            | 0 to 18446744073709551615                  |
// | Float  | 4bytes            | 1.2E-38 to 3.4E+38 (~6 digits)             |
// | Double | 8bytes            | 2.3E-308 to 1.7E+308 (~15 digits)          |
// +--------+-------------------+--------------------------------------------+

// Type Aliases:
//
    typealias Feet = Int
    var distance: Feet = 100
    print(distance)

// Type inference:
//
// varA is inferred to be of type Int
    var varA = 42
    print(varA)
//
// varB is inferred to be of type Double
    var varB = 3.14159
    print(varB)
//
// varC is also inferred to be of type Double
    var varC = 3 + 0.14159
    print(varC)