Create a Currency Convert app that can convert from US dollars (USD) to Canadian dollars (CAD) and Mexican Pesos (MXN).

Get the currency conversion value from Google:

On August 7th, 2019 they were:

$1 USD to $1.33 CAD
$1 USD to $19.70 MXN

Currency Converter App

1. Create a currency type enum above the class and below the import statements.

   enum Currency {
       case cad
       case mxn
   }

2. Create a property named currency of type Currency. This will store the current currency type we'll be converting to. Set an initial value of .cad.

3. In the cadButtonTapped action:

   • Toggle this button's isSelected state
   • Toggle the mxn button's isSelected state
   • Check this button's state, and if true:
     • set the currency property to .cad
     • Display the currency in the toCurrencyLabel (so have it say "Currency (CAD)")

4. In the mxnButtonTapped action:

   • Toggle this button's isSelected state
   • Toggle the cad button's isSelected state
   • Check this button's state, and if true:
     • set the currency property to .mxn
     • Display the currency in the toCurrencyLabel (so have it say "Currency (MXN)")

5. Create a helper method to calculate the currency based on the Currency using the method signature:

   func convert(_ dollars: Double) -> Double {
   }

6. In the above method:

   • Check the value of currency to see whether you should convert to CAD or MXN
   • Perform the conversion with the dollars passed into this method
   • Return the converted value

7. In the convertButtonTapped() action method:

   • use a guard let to get user input
   • convert the dollar amount to the expected currency (hint, you'll want to call the convert method you created in step 5)
   • Update the toCurrencyTextField.text property with the converted currency value

1. Customize the output display using a NumberFormatter

   var currencyFormatter: NumberFormatter = {
       let formatter = NumberFormatter()
       formatter.numberStyle = .currency
       return formatter
   }()

2. Use the string(from:) method to convert from a number to a String for display