A playground for calculating hours and minutes into fractional hours i.e. 4 hours and 12 minutes should be 4.2 hours.

roundClock.swift

/// A function for calculating the time in 0.1 hour increments
/// i.e. 1 hour and 6 min is 1.1hours, 3 hours 12 minutes is 3.2 hours
func calc(hours: Int, min: Int) -> Double {
    let dbl = Double(min)
    let roundedMin = (dbl / 60.0)
    let flr = floor(roundedMin * 10 ) / 10
    return Double(hours) + floor(roundedMin * 10) / 10
}

/// How to round a number?

/// Given some number of hours and minutes, we want to round those to be a decimal
/// representation of the hours worked in the week

//for example give 1 hour and 6 minutes we should have 1.1 hours

//let h = 1
//let m = 6
//
//let total = calc(h, m)


// What about 7 minutes, clearly that is closer to 1.1 hours than it is to 1.2 hours

//let h2 = 1
//let m2 = 7
//
//let t2 = calc(h2, m2)

/// how can we modify our calc function to round off the rest of those digits,
/// Lets make it easy on our selves and only look at 2 digits

/// Using the round function we may be able to get close

//let h3 = 2
//let m3 = 11 //lets see if 11 gets rounded up?
//
//let t3 = calc(h3, m3) //sweet

/// Check the middle numbers to be sure
/// if 6 is the 0.1 and 12 is 0.2 , 9 will be right in the middle

/// So 8 should round down 

//let h4 = 2
//let m4 = 8
//let t4 = calc(h4, m4)

/// and 9 will round up

//let h5 = 2
//let m5 = 9
//let t5 = calc(h5, m5)

// running the above function on a full hour worth of minutes we should see a nice stair step pattern with jumps at 6,12,18,etc.

let minutes = Array(1..<60)
let frac = map(minutes){ 
    calc(0, $0) 
}
frac