iOS Swift Getting Started note

Define constants: Let MAX = 3; (after the statement ends, you can add a semicolon, or no semicolon)
Define variables: var max = 3;var str = "Hello world";
Defines the specified type variable: var value:int = 3; (The type is specified at this time)
Output statement: println (max);
Multivariable output: println ("x1 = (a), x2 = (b), x3 = (c)");

Swift Data type:
Shaped, signed and unsigned:
Int Int8 Int16 Int32
UInt UInt8 UInt16 UInt32
When a 64-bit system, Int = Int64, UInt = UInt64

float, double

let decimal = 20;
Let binary = 0b1100
Let octal = 0o21
Let hex = 0x11

Readability:
Let value = 12_000_000
Let value2 = 12_000_000.000_1

BOOL Type

iOS Swift Getting Started note