Data Types

Relax. We'll talk through this in plain words — no textbook voice.

Swift is a type-safe language. That means the compiler always knows exactly what data type a variable holds. This lets it catch mistakes early — like putting text into a number, or a boolean into a string.

In Swift, you can write out a type explicitly, or let the compiler figure it out from the value — this is called type inference.

swift

let name: String = "Nandar"   // Explicit type
let age = 24                 // Int လို့ compiler ကခန့်မှန်းမယ်
let rating = 4.8             // Double
let isPremiumUser = true     // Bool

print("\(name) is \(age) years old.")
print("Rating: \(rating), Premium: \(isPremiumUser)")

String is for text, Int is for whole numbers, Double is for decimal numbers, and Bool is for true/false values. \(...) is called string interpolation, and it lets you drop a variable's value right into a string.

You should see

Nandar is 24 years old. Rating: 4.8, Premium: true

Easy traps

After let age = 24, you can't assign age = "twenty four" — the types don't match, so it will throw an error.