## Day 8 Throwing Functions, Generalizing the function

 Apr '24 I have a question regarding gereralizing throwing functions, specifically with regard to addind the do/catch to it's own function. The examples in 100 Days of SwiftUI as well as other documentation I found online shows that to use throwing functions, we should create an enum, a function, and then use do/catch to try the code. My question is where should the do catch go? What is the best way to generalize it? In the Day 8 example that I used to guide my code for Checkpoint 4 - Integer square, it seems that I should hardcode the square. See the example in the the section labeled "START ORIGINAL EXAMPLE" where I created a function, "integerSquare" I then decided to to rename "integerSquare" to integerSquareRunner, that gets called by "integerSquare." That way, "integerSquare" could be called with different inputs, such as: integerSquare(of: 15) That code can be found in the section labeled "START UPDATED EXAMPLE" It works as I intended, but is this good practice? Is there another way that this same functionality can be accomplished? Thank you in advance... ``````import UIKit enum SquareRootError: Error { case outOfBounds, noRoot }`````` // **** START ORIGINAL EXAMPLE /* ``````func integerSquare(of num: Int) throws -> Int { if num < 1 || num > 10000 { throw SquareRootError.outOfBounds} for i in 1...10000 { if i * i == num { return i } } throw SquareRootError.noRoot } do { var square = try integerSquare(of: 10000) print(square) } catch SquareRootError.outOfBounds { print("The number that you entered is out of bounds.") } catch SquareRootError.noRoot { print("There is no perfect root for number that you entered.") }`````` */ //**** END ORIGINAL EXAMPLE // **** START UPDATED EXAMPLE ``````func integerSquareRunner(of num: Int) throws -> Int { if num < 1 || num > 10000 { throw SquareRootError.outOfBounds} for i in 1...10000 { if i * i == num { return i } } throw SquareRootError.noRoot } func integerSquare(of num: Int){ do { var square = try integerSquareRunner(of: num) print(square) } catch SquareRootError.outOfBounds { print("The number that you entered is out of bounds.") } catch SquareRootError.noRoot { print("There is no perfect root for number that you entered.") } catch { print("There was an error: \(error.localizedDescription)") } }`````` `integerSquare(of: 15)` //**** END UPDATED EXAMPLE Apr '24 Please edit your post and put ALL YOUR CODE inside the code markup tags. Thanks. Apr '24 You should put the `do ... catch` wherever you plan to handle the error. Creating a whole new function just to have somewhere to catch errors is overcomplicating things. Your first example is the way to go. 1 Apr '24 You can reduce the amount of zeros here to 100..... ``for i in 1...10000 {`` You are returning i x i from range 1 to 10000. 100 x 100 is 10000. 100 x 101 is higher than 10000, so there's not much point in that. As far as do and catch goes try not to write code that will crash :)! Apr '24 I would change a few thing (not sure that you have covered this in the 100Days) but use a `guard` instead of `if` in the method. At the moment you are learning about them and can not see how they would work so did this as an example. You have a model `class` that you would put the throwing method in ``````@Observable class SomeModel { var inputNumber = 0 func squareRoot(of num: Int) throws -> Int { guard num > 1 && num < 10000 else { throw SquareRootError.outOfBounds } for i in 1...100 { if i * i == num { return i } } throw SquareRootError.noRoot } }`````` Then in the `View` it can be used ``````struct ContentView: View { @State private var model = SomeModel() var displaySquareRoot: String { do { let root = try model.squareRoot(of: model.inputNumber) return "Answer: \(root)" } catch SquareRootError.outOfBounds { return "The number that you entered is out of bounds." } catch SquareRootError.noRoot { return "There is no perfect root for number that you entered." } catch { return "There was an error: \(error.localizedDescription)" } } var body: some View { VStack { LabeledContent("Enter Number: ") { TextField("Enter Number", value: \$model.inputNumber, format: .number) .textFieldStyle(.roundedBorder) .multilineTextAlignment(.center) } Text(displaySquareRoot) .padding() } .padding() } }`````` As you can see that handling errors at the call site to display to user.

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