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iOS Object-Oriented Swift Properties Getter and Setter Methods

Carter Selman
Carter Selman
1,660 Points
Posted by Carter Selman
Carter Selman
1,660 Points

Getter and Setter

I don't quite understand the use of the Getter and Setter, but can someone please try to explain to me why this code is wrong. Thank you!

Temperature.swift 
class Temperature {
    var celsius: Float = 0.0
    var fahrenheit: Float {
    get {
        return (celsius * 1.8) + 32.0
        }
    set {
        celsius = (fahrenheit - 32)/1.8
    }
    }    
}

1 Answer

Jhoan Arango
Jhoan Arango
14,575 Points
Jhoan Arango
Jhoan Arango
14,575 Points

Hello there

  • Computed Properties

“In addition to stored properties, classes, structures, and enumerations can define computed properties, which do not actually store a value. Instead, they provide a getter and an optional setter to retrieve and set other properties and values indirectly.”

Excerpt From: Apple Inc. “The Swift Programming Language (Swift 2 Prerelease).” iBooks. https://itun.es/us/k5SW7.l

So we know that a computer property is just a read-only property, where you can’t capture the value and use it somewhere else, it ONLY computes something and displays it (if you can say it like that).

class Temperature {
    var celsius: Float = 0.0
    var fahrenheit: Float {
    get {
        return (celsius * 1.8) + 32.0
        }
    set {
        celsius = (newValue - 32)/1.8 
    }
    }    
}

var temp = Temperature()

temp.fahrenheit = 89 // newValue being passed

In this challenge in order of us to set a value to the celsius property we can use the newValue keyword, this will set the value passed through the fahrenheit computer property.

Hope you understand a bit more.