Read-Only properties

Question

I need help with "read-only" in swift. I tried various ways, but simply couldn't figure out how to compile it without errors. Here's the question and what i thought of.

Create a read-only computed property named isEquilateral that checks to see whether all three sides of a triangle are the same length and returns true if they are and false if they are not.

var isEquilateral: Int {  } 

Answer 1

If you want a "read-only" stored property, use private(set):

private(set) var isEquilateral = false 

If it is a property calculated from other properties, then, yes, use computed property:

var isEquilateral: Bool {     return a == b && b == c } 

---

For the sake of completeness, and probably needless to say, if it is a constant, you’d just use let:

let isEquilateral = true 

Or

struct Triangle {     let a: Double     let b: Double     let c: Double      let isEquilateral: Bool      init(a: Double, b: Double, c: Double) {         self.a = a         self.b = b         self.c = c          isEquilateral = (a == b) && (b == c)     } } 

Answer 2

Something like this? (as suggested by @vacawama in the comments)

struct Triangle {     let edgeA: Int     let edgeB: Int     let edgeC: Int      var isEquilateral: Bool {         return (edgeA, edgeB) == (edgeB, edgeC)     } } 

Let's test it

let triangle = Triangle(edgeA: 5, edgeB: 5, edgeC: 5) triangle.isEquilateral // true 

or

let triangle = Triangle(edgeA: 2, edgeB: 2, edgeC: 1) triangle.isEquilateral // false