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iOS

Posted by Jason Larkin
Jason Larkin
13,970 Points

Struct Methods Challenge 4/4 Can't get it

I'm stuck on this last question in the structs methods challenges. The instructions are: to figure out the tax amount when the tax percentage is 7.5 percent. Call the method calculateTaxes on the variable item and assign the result to a new variable named taxes. Can anyone please help me?

struct Expense {
    var description: String
    var amount: Double = 0.0

    init (description: String) {
        self.description = description
    }
              func calculateTaxes(percentage: Double) -> Double{
        return (self.amount * (percentage/100))


    }
    // it should accept only one parameter named 'percentage' of type Double

}

var item = Expense(description: "Taxes"); item.amount = 100
var taxes = item(calculateTaxes); taxes.amount = 7.5

2 Answers

Stone Preston
Stone Preston
42,016 Points

Task 4 states: . Call the method calculateTaxes on the variable item and assign the result to a new variable named taxes

you can call a function on an instance of a struct using dot syntax. 

someInstance.someFunction()

in this case you need to call the function calculateTaxes on your item instance and pass in 7.5 as the argument. you need to assign the return value of that to a variable named taxes. it should look something like this

var taxes = item.calculateTaxes(7.5)
Jason Larkin
Jason Larkin
13,970 Points

Thank you Stone- my brain is fried so thanks for providing another set of eyes!

Philip Ondrejack
Philip Ondrejack
4,287 Points
Philip Ondrejack
Philip Ondrejack
4,287 Points

I've been working on this in Xcode and I'm not getting an error code when I use:

var taxes = Expense.calculateTaxes(item)

What is this line of code actually doing? I'm calling calculateTaxes on Expense and passing it item? I can't get it to println() a result no matter what I try.