Doubles and Floats

let price = 19.99
let taxRate = 0.08
print("Price: \(price), tax rate: \(taxRate)")

let preciseValue: Double = 3.14159265358979
let lessPrecise: Float = 3.14159265358979
print("Double: \(preciseValue)")
print("Float: \(lessPrecise)")

let items = 3
let totalCost = 10.0
let average = totalCost / Double(items)
print("Average cost per item: \(average)")

1. Comparing two Double values with == after arithmetic and expecting exact equality, when floating-point rounding can make them differ slightly.
2. Using Float when Double is intended; Double is Swift's default and has more precision, so mixing them requires explicit conversion.
3. Dividing two Int values expecting a decimal result, forgetting that Int / Int truncates instead of producing a Double.

• Double is a 64-bit floating-point type and Swift's default choice for decimal numbers.
• Float is a 32-bit floating-point type, less precise but sometimes used to save memory.
• Floating-point arithmetic can have small rounding errors, so avoid exact == comparisons.
• Converting an Int to a Double requires an explicit Double(someInt) call.