SwiftUI Tutorial (14 day tutorial), lesson 9, challenge: error in solution

App Development
1

Hi Chris,

In your solution your return in the struct BillSplitter is “totalWithTax/4” That will result in the same value regardless the numPeople input.

My return is “totalWithTax/Double(numPeople)”
Then the calculation with 5 people in the exercise is working.

2

Hi Hendrik,

Welcome to the code crew community.

Can you show the code that you have. Sounds like something is not quite right.

This is the code that I have for the exercise:

struct TaxCalculator {
    let tax: Double = 0.1
    
    func totalWithTax(inputValue: Double) -> Double {
        let taxAmount = inputValue * tax
        return inputValue + taxAmount
    }
}

struct BillSplitter {
    
    let taxCalculator = TaxCalculator()
    
    func splitBy(subTotal: Double, numberOfPeople: Int) -> Double {
        let totalCost = taxCalculator.totalWithTax(inputValue: subTotal)
        return totalCost / Double(numberOfPeople)
    }
}

let billSplitter = BillSplitter()
let eachMustPay = billSplitter.splitBy(subTotal: 120, numberOfPeople: 5)
let stringValue = String(format: "%.2f", eachMustPay)
print("$\(stringValue)")
3

Hi,

This is the solution I downloaded in November (official resources, see link below) (and there is no change, I just checked):

Bildschirmfoto 2020-12-23 um 15.56.03
Bildschirmfoto 2020-12-23 um 15.56.031554×1032 131 KB

As you can see, the return from the struct BillSplitter is fixed to 4 people.
In your code (as well as in my solution), the “4” is exchanged by “Double(numberOfPeople)” or similar.

4

the return statement at line 17 should be:

return totalWithTax / numPeople
5

Yes.

My point is:
This is the solution from CodeWithChris.
The solution for students contains the error.

6

Yep, I see that.

Look at it from the point of view that you were able to debug the code and figure it out by yourself. :+1:

I have notified Chris Ching so it will be corrected when he gets a chance. He is probably busy with the festive season I suspect.

1 Like
7

Hi Chris,

In line 17, it seems to me that totalWithTax/numPeople will result in a Double being divided by an Int - because in line 12 numPeople is set to type Int.

This same code is present in the solution as well.

Not sure if I am missing as this is my first time with Swift.

regards,
Bhargava

8

Yes you are right. This was supposed to have been corrected in the solution by wrapping numberOfPeople with Double() like this:

Double(numberOfPeople)

I’ll contact Chris Ching to have that fixed.

Look at it from the point of view that you were able to debug the code and figure it out by yourself. :+1:

9

Debugging is fun, but still: little reminder that the error is still in the student material I downloaded a few days ago. :wink:

1 Like