Swift3.0基础语法学习<五>

异常处理：

 1 //
 2 //  ViewController5.swift
 3 //  SwiftBasicDemo
 4 //
 5 //  Created by 思 彭 on 16/11/16.
 6 //  Copyright ? 2016年 思 彭. All rights reserved.
 7
 8 // 错误处理
 9
10 import UIKit
11
12 class ViewController5: UIViewController {
13
14     override func viewDidLoad() {
15         super.viewDidLoad()
16         self.title = "错误处理"
17
18         // 1.函数内的 throws异常处理
19         func send(job: Int, toPrinter printrName: String) throws ->String {
20             if  printrName == "Never Has Toner" {
21                 throw PrintError.noToner
22             }
23             return  "Job sent"
24         }
25
26         // 2.do...catch处理异常   输出： Job sent
27         do {
28
29             let  printerresponse = try send(job: 1040, toPrinter: "Bi Sheng")
30             print(printerresponse)
31         }catch {
32             print("error = \(error)")
33         }
34
35         // 3.
36         do {
37             let printerResponse = try send(job: 1440, toPrinter: "Gutenberg")
38             print(printerResponse)
39         } catch PrintError.onFire {
40             print("I‘ll just put this over here, with the rest of the fire.")
41         } catch let printerError as PrintError {
42             print("Printer error: \(printerError).")
43         } catch {
44             print(error)
45         }
46     }
47
48     // 定义“打印错误”的枚举
49     enum PrintError: Error {
50         case outOfPaper
51         case noToner
52         case onFire
53     }
54 }