Stuck At - Use getters and setters to Control Access to an Object

[deetigupta8]

Hi, I can’t identify what’s wrong with the code I have written.
I can’t pass the test -
Calling the setter with a Celsius value should set the temperature .

Hereby is the code -

class Thermostat{
  constructor(Ftemp){
this._Ftemp = Ftemp;
  }
  get temperature(){
return  5/9 * (this._Ftemp - 32);
  }
  set temperature(CTemp) {
this._Ftemp = CTemp;
  }
}

Thanks for helping :)

[KittyMac]

Hi Deeti

Inside your Thermostat class, you’re storing the temperature in Fahrenheit, so your setter needs to convert from Celsius to Fahrenheit.

One minor point - your variable names aren’t in camel case.
Using cTemp and fTemp (or tempF and tempC, which I think are more readable) would be better.

[kevinSmith]

You don’t have a link to the problem so it is hard to test, but looking at it,

  set temperature(CTemp) {
this._Ftemp = CTemp;
  }

You are saving the passed in celsius into a fahrenheit variable? Shouldn’t there be a conversion there?

[deetigupta8]

I tried this code below, but I am getting syntax error now.

class Thermostat{
  constructor(fTemp){
this._fTemp = fTemp;
  }
  get temperature(){
return this._fTemp;
  }
  set temperature(cTemp) {
 5/9 * (this._fTemp - 32) = cTemp;
  }
}

Link to the problem -

freeCodeCamp.org

Thank you

[deetigupta8]

I tried this code below, but I am getting syntax error now.

class Thermostat{
  constructor(fTemp){
this._fTemp = fTemp;
  }
  get temperature(){
return this._fTemp;
  }
  set temperature(cTemp) {
 5/9 * (this._fTemp - 32) = cTemp;
  }
}

Link to the problem -

freeCodeCamp.org

Thank you

[kevinSmith]

@deetigupta8

5/9 * (this._fTemp - 32) = cTemp;

RIght, it should just be this.fTemp on the left side of the assignment.

[deetigupta8]

Oh, yeah! Thanks.

But now 2 tests are failing including - When instantiated with a Fahrenheit value, Thermostat should set the correct temperature .

[deetigupta8]

And finally this one-

class Thermostat{
  constructor(fTemp){
this._fTemp = fTemp;
  }
  get temperature(){
return this._fTemp;
  }
  set temperature(cTemp) {
 cTemp = 5/9 * (this._fTemp - 32);
  }
}

Now one more function is not passing-
When instantiated with a Fahrenheit value, Thermostat should set the correct temperature .

Thank you

[KittyMac]

Hi Deeti

Ok, you have two problems.

Your getter:

• the code in your original post was OK for your getter
• it converts this.fTemp to Celsius and returns the Celsius value, which is what it should do
• so, put that code back into your getter (change Ftemp to fTemp) and just run the tests again to be sure that’s ok

Your setter:

• this needs to receive a Celsius temperature cTemp, convert it to Fahrenheit, and store it in this.fTemp
• so , first of all you need to use a different conversion formula here
• from the instructions the formula is F = C * 9.0 / 5 + 32
• and then, as @kevinSmith pointed out, you need to store the result in this.fTemp
• like this this.fTemp = the_result_of_your_conversion

Does that make sense?

[deetigupta8]

Not sure how much I understand. If we are using get to access the property, then why are we returning the converted celcius value in get?

I am assuming set functions modify the fahrenheit value to celcius.
From the logic above following code makes sense:

class Thermostat{
  constructor(fTemp){
this._fTemp = fTemp;
  }
  get temperature(){
return this._fTemp;
  }
  set temperature(cTemp) {
 cTemp = 5/9 * (this._fTemp - 32);
  }
}

However, the correct code is:

class Thermostat{
  constructor(fTemp){
this._fTemp = fTemp;
  }
  get temperature(){
return  5/9 * (this._fTemp - 32);
  }
  set temperature(cTemp) {
 this._fTemp = cTemp * 9.0 / 5 + 32
  }
}

Above, get is converting fTemp to cTemp., which looks like a job pf a setting function.
and set function is assigning value to fTemp by modifying cTemp to fTemp. Not sure what’s going on.

Thanks for getting back and explaining

[KittyMac]

Well, the aim of this exercise is to demonstrate hiding the details of “how this is implemented”.

So, you (the developer) can choose whether you want to store the temperature in fahrenheit or celsius.

That’s what this part of the instructions means:

When you implement this, you will track the temperature inside the class in one scale, either Fahrenheit or Celsius.

You chose fahrenheit (because you stored a fahrenheit temperature in the constructor).
But you could have chosen to convert that temperature to celsius, and to store it as a celsius value.

The important point is that, the code that uses your Thermostat class doesn’t need to know which choice you made .

The developer of that code just needs to know

• how to create a Thermostat object (i.e. supply a fahrenheit value)
• and that calling the getter/setter will return/accept a celsius value.

It’s a bit of a contrived example, though.
So I really wouldn’t worry too much about this one - I think it will all make more sense when you’ve had some more practice with classes and objects.