Swift Data Types

Basic Swift Data Types

let count: Int = 42
let negative: Int = -10

let message: String = "Hello"
let emoji: String = "🚀"

let isReady: Bool = true
let isComplete: Bool = false

let price: Double = 19.99
let pi: Double = 3.14159

🔹 Integer Types

Swift provides several integer types for different ranges:

// Standard integer type
let age: Int = 25
let year: Int = 2024

// Specific bit-width integers
let smallNumber: Int8 = 127    // -128 to 127
let mediumNumber: Int16 = 32767 // -32,768 to 32,767
let largeNumber: Int64 = 9223372036854775807

// Unsigned integers (positive only)
let positiveOnly: UInt = 100
let smallPositive: UInt8 = 255  // 0 to 255

print("Age: \(age)")
print("Year: \(year)")

🔹 Floating-Point Types

Use Float and Double for decimal numbers:

// Double (64-bit, more precise)
let preciseNumber: Double = 3.141592653589793
let price: Double = 29.99

// Float (32-bit, less precise)
let simpleFloat: Float = 3.14
let temperature: Float = 98.6

// Swift prefers Double by default
let defaultDecimal = 2.5  // This is Double

print("Price: $\(price)")
print("Temperature: \(temperature)°F")

🔹 String Type

Strings store text and support Unicode characters:

// Basic strings
let firstName: String = "John"
let lastName: String = "Doe"

// String interpolation
let fullName = "\(firstName) \(lastName)"

// Multi-line strings
let poem = """
Roses are red,
Violets are blue,
Swift is awesome,
And so are you!
"""

// Unicode and emojis
let greeting = "Hello 👋"
let flag = "🇺🇸"

print(fullName)
print(greeting)

🔹 Boolean Type

Bool represents true or false values:

// Boolean literals
let isLoggedIn: Bool = true
let hasPermission: Bool = false

// Boolean from comparisons
let isAdult = age >= 18
let isWeekend = dayOfWeek == "Saturday" || dayOfWeek == "Sunday"

// Using booleans in conditions
if isLoggedIn {
    print("Welcome back!")
} else {
    print("Please log in")
}

// Boolean operations
let canAccess = isLoggedIn && hasPermission
print("Can access: \(canAccess)")

🔹 Character Type

Character represents a single character:

// Single characters
let firstLetter: Character = "A"
let symbol: Character = "@"
let emoji: Character = "🎉"

// Building strings from characters
let chars: [Character] = ["H", "e", "l", "l", "o"]
let word = String(chars)

print("First letter: \(firstLetter)")
print("Word: \(word)")