Computed Properties in Structs
Deriving values with get-only and get/set computed properties.
Welcome
Computed properties don't store a value — they compute and return one on demand. They look like properties to callers but run code under the hood.
Read-Only Computed Property
```swift
struct Circle {
var radius: Double
var area: Double { .pi * radius * radius }
var circumference: Double { 2 * .pi * radius }
}
var c = Circle(radius: 5)
print(c.area) // 78.53...
```