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iOS Swift Basics (retired) Operators Binary Operators

Lim Shan Kuo
Lim Shan Kuo
16,049 Points

How a constants becomes mutable when a Double(area) applied? Plus its a compile language

let area = width * height
let areaInMeters = Double(area) / 10.764

constant variable area defined as int type then a Double function to change int type to double. I try understand from a compiler language angle.

1 Answer

Stone Preston
Stone Preston
42,016 Points

the constant area does not become mutable. it does not change at all. constants values cannot change once they are set

let areaInMeters = Double(area)

passes the constant area in as an argument to the Double initializer and a new constant, areaInMeters, is created with the same value as area.

area is unchanged. it is not modified. area and areaInMeters are two completely different constants