Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

iOS Swift Enums and Structs Structs and their Methods Struct Methods

Paula Carvajal
Paula Carvajal
1,679 Points

how to call a method on a variable

I am working on one of the challenges and I am not sure how to solve it, please help: We need 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.

struct.swift
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))
}

}
var item = Expense(description: "Spent money")
item.amount = 100.00

item.calculateTaxes (item.amount * 7.5/100)
var taxes = calculateTaxes

1 Answer

Chase Marchione
Chase Marchione
155,055 Points

Hi Paula,

To call a method on a variable, the syntax is 'variable.method()'. In this case, our variable is item and the method is calculateTaxes, so it's item.calculateTaxes(), with our argument inside of the parentheses. We'll store the result of this method call statement to our taxes variable (since this method statement will return the value that we want to store in the taxes variable.)

var taxes = item.calculateTaxes(item.amount * 7.5/100)

Hope this helps!