Converting String to Int with Swift

Question

The application basically calculates acceleration by inputting Initial and final velocity and time and then use a formula to calculate acceleration. However, since the value

Answer 1

As of swift 3, I have to force my #%@! string & int with a "!" otherwise it just doesn't work.

For example:

let prefs = UserDefaults.standard
var counter: String!
counter = prefs.string(forKey:"counter")
print("counter: \(counter!)")


var counterInt = Int(counter!)
counterInt = counterInt! + 1
print("counterInt: \(counterInt!)")

OUTPUT:
counter: 1
counterInt: 2