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iOS Object-Oriented Swift Properties Getter and Setter Methods

Jan Vrzal
Jan Vrzal
3,687 Points
Posted by Jan Vrzal
Jan Vrzal
3,687 Points

Where is the problem ?

error: The setter method for fahrenheit did not assign the right value to the celsius property. (Note: Celsius = (Fahrenheit-32)/1.8)

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
    }
    }    
}

2 Answers

Tommy Choe
Tommy Choe
38,156 Points
Tommy Choe
Tommy Choe
38,156 Points

Hey Jan,

don't forget to use the special keyword "newValue" to get the value that is being set. Replace "fahrenheit" with "newValue" and you should be able to pass the challenge.

Hope that works!

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.”

So we know that a computed 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 for us to set a value to the celsius property we can use the newValue keyword, this will set the value passed through the fahrenheit computed property.

Hope you understand a bit more.