Kiểu dữ liệu Số (Int, Double, Float)

1. Integers

let int: Int = 42
let int8: Int8 = 127
let int16: Int16 = 32767
let int32: Int32 = 2147483647
let int64: Int64 = 9223372036854775807

// Unsigned
let uint: UInt = 100
let uint8: UInt8 = 255

2. Floating-Point

let double: Double = 3.14159  // 64-bit (mặc định)
let float: Float = 3.14       // 32-bit

3. Type Safety

let int = 42        // Int
let double = 3.14   // Double

// let sum = int + double  // Error!
let sum = Double(int) + double  // OK

4. Number Literals

let decimal = 17
let binary = 0b10001
let octal = 0o21
let hex = 0x11

// Underscore
let million = 1_000_000

5. Type Conversion

let int = 100
let double = Double(int)
let float = Float(int)
let string = String(int)

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📝 Tóm tắt

• Int (mặc định), Double (mặc định số thực)
• Type safe - phải convert tường minh
• _ để dễ đọc
• 0b (binary), 0o (octal), 0x (hex)