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This article introduces the relevant knowledge of "how to understand swift error handling". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

Enum VendingMachineError: Error {case invalidSelection case insufficientFunds (coinsNeeded: Int) case outOfStock} struct Item {var price: Int var count: Int} class VendingMachine {var inventery = ["Candy Bar": Item (price: 12, count: 7), "Chips": Item (price: 10, count: 4), "Pretzels": Item (price: 7) Count: 11)] var coinsDeposited = 0 func vend (itemNeed name: String) throws {guard let item = inventery [name] else {throw VendingMachineError.invalidSelection} guard item.count > 0 else {throw VendingMachineError.outOfStock} guard item.price Int {/ / return 1} let x = try? SomeThrowingFunction () / equivalent let y: Int?do {y = try someThrowingFunction ()} catch {y = nil} try! Interrupt error propagation

If an error does occur, you will get a runtime error

/ / try! Interrupt error propagation, and if the error does occur, you will get the runtime error let photo = try! SomeThrowingFunction () defer cleanup action before exiting / / specify the cleanup action before exiting defer keyword func processFile (filename: String) throws {if exists (filename) {let file = open (filename) defer {close (file)} while let line = try file.readline () {/ /} /} "how to So much for understanding swift error handling. Thank you for your reading. If you want to know more about the industry, you can follow the website, the editor will output more high-quality practical articles for you!

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