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# I Problems with set method in computed properties

I having problems understanding the error message, and what I am doing wrong

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

Hi Victor,

Getters and Setters are a bit weird and difficult to understand - they always confuse me! But that's quite easy!

The challenge wants you to create a getter for `fahrenheit` that uses the existing `celsius` value to calculate the conversion. The code provided at the start of the challenge does this. You just need to add the `get` bit to it:

```class Temperature {
var celsius: Float = 0.0
var fahrenheit: Float {
get {
return (celsius * 1.8) + 32.0
}
set {
// do something
}
}
}
```

That just leaves the setter to complete.

Essentially, the setter will change the value of `celsius` when the function is passed a value to `fahrenheit`. So, the calculation needs to be reversed, i.e. subtract 32 then divide by 1.8. The calculation is performed on the `newValue` which is the number passed into the function:

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

So, create am instance of Temperature and initialise it so `celsius` has a value of 32.

Typing `temp.celsius` will output 32. Looking at `temp.fahrenheit` will give you 89.59 using the `get` part of the function.

To use the `set` part, pass a value to `fahrenheit` like:

Enter `temp.fahrenheit = 90` Then, `temp.celsius` will give you 15.55

So, you can influence each variable by changing the value of the other since they are mutually linked in that way.

Hope that helps,

Steve.