I have a simple task, but I am unable to find a solution. I'm making baby steps toward the eventual goal of creating an app that calculates annual earnings based on a fixed array of hourly pay rates that steadily increase yearly. The user will input the number of monthly hours worked and their company year group (defining which pay rate applies/where to start in the pay rate array).

My current baby step is to create a simplified verision: the hour pay rate is static.

The only error that my macOS Command Line Tool complies is "Function call causes an infinite recursion"

import Foundation

let pennyRoundingBehavior = NSDecimalNumberHandler(
    roundingMode: .bankers,
    scale: 2,
    raiseOnExactness: false,
    raiseOnOverflow: true,
    raiseOnUnderflow: true,
    raiseOnDivideByZero: true
)

func roundToNearestPenny(rate: Decimal, of dollarAmount: Decimal) -> Decimal
{
    assert((0...100).contains(rate))

    let x = ((dollarAmount * rate) as NSDecimalNumber)
    return x.rounding(accordingToBehavior: pennyRoundingBehavior) as Decimal
}

enum EmploymentYears: Int, CaseIterable
{
 case Year1, Year2, Year3, Year4, Year5, Year6, Year7, Year8, Year9, Year10

    static var count:Int  { allCases.count }
}

struct YearlyEarnings
{
    var yearlyEarnings  : Decimal = 0

    init(monthlyHoursWorked: Decimal, payRate: Decimal)
    {
        let yearlyEarnings = roundToNearestPenny(
            rate: payRate,
            of: monthlyHoursWorked
        )
        self.init(monthlyHoursWorked: monthlyHoursWorked, payRate: payRate)  // < -- error is here
    }
}

extension Array where Element == YearlyEarnings {
    subscript (index: EmploymentYears) -> Element { self[index.rawValue] }
}

func computeYearlyEarnings(
    monthlyHoursWorked   : Decimal,
    rate                 : Decimal) -> [YearlyEarnings]
{
    var yearlyEarnings: [YearlyEarnings] = []
    yearlyEarnings.reserveCapacity(EmploymentYears.count)

    let yearlyEarning = roundToNearestPenny(
        rate: rate,
        of: monthlyHoursWorked
    )

    return yearlyEarnings
}

var monthlyHoursWorked   : Decimal = 160.0
var rate                 : Decimal = 20.0

let yearlyEarnings = YearlyEarnings(
    monthlyHoursWorked: monthlyHoursWorked,
    payRate: rate
)

for year in EmploymentYears.allCases
{
    let curEarning = yearlyEarnings
    print("Earnings for \(year)")
    print("    $\(curEarning.yearlyEarnings)")
    print()
}

I replaced

self.init(monthlyHoursWorked: monthlyHoursWorked, payRate: payRate)

with

self.init(yearlyEarnings: yearlyEarnings)

but that produced the following two errors: "Extra argument 'yearlyEarnings' in call" & "Missing arguments for parameters 'monthlyHoursWorked', 'payRate' in call"

@roosterboy Thank you! I wasn't sure where to multiply by 12 to make this a yearly result and not a monthly one. It seems to work with the following adjustment:

func roundToNearestPenny(rate: Decimal, of dollarAmount: Decimal) -> Decimal
{
    assert((0...100).contains(rate))

    let x = ((dollarAmount * rate) * 12 as NSDecimalNumber)
    return x.rounding(accordingToBehavior: pennyRoundingBehavior) as Decimal
}