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SOLVED: Day 19: Challenge Day

Forums > 100 Days of SwiftUI

I am having hard time to understand and excute the messuermesnt coding part, can someone explain it to me please

I have looked into to How to convert units using Unit and Measurement article but i am still stuck and tried several times and still not working.

struct ContentView: View {

    @State private var inputNumber = ""
    @State private var inputUnit   = 0
    @State private var outputUnit  = 0

    let conversionUnit  = ["Kilometers", "Miles", "Meters"]

    var totalconversion: Double {
        let total = Double(inputNumber) ?? 0

        return 0


    var body: some View {
        NavigationView {
            Form {
                Section(header: Text("Please enter the amount")) {

                    TextField("Enter here", text: $inputNumber)
                    Text("Choose Your Input Unit")
                    Picker("From Unit", selection: $inputUnit) {
                        ForEach(0 ..< conversionUnit.count) {
                }       .textCase(nil)

                Section {
                    Text("Choose Your Output Unit")
                    Picker("To Unit", selection: $outputUnit) {
                        ForEach(0 ..< conversionUnit.count) {

                    Text("\(outputUnit, specifier: "%.2f")")

            .navigationBarTitle("Unit Converter")


struct ContentView_Previews: PreviewProvider {
    static var previews: some View {


You can convert from one Measurement to another. Which means you first must take the input and turn it into a specific unit of measurement.

So if the user enters 10, you need to be able to convert it to an actual unit. Something like this:

let baseUnit = Measurement(value: Double(inputUnit) ?? 0, unit: UnitLength.kilometers)

//This allows you to then convert like so

let finalUnit = baseUnit.converted(to: UnitLength.miles)

The user inputs a number which we get as a String, they then set the initial measurement unit and final one. So we need to turn the String into a Double so we can apply math or use it like above, then based on their initial and final units, choose the right conversion.

That should get you going I hope.

edit: One more thing to note here is that if you want to be able to format the result of the conversion you should use:

let finalUnit = baseUnit.converted(to: UnitLength.miles).value

This will be a Double.


@MarcusKay thank you i finally figured it out


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