Swift基础之函数定义

 1 //
 2 //  ViewController.swift
 3 //  SwiftLesson3
 4 //
 5 //  Created by 薛雨仑 on 14-10-2.
 6 //  Copyright (c) 2014年 Dylan. All rights reserved.
 7 //
 8 
 9 import UIKit
10 
11 class ViewController: UIViewController {
12 
13     override func viewDidLoad() {
14         super.viewDidLoad()
15         
16         println(self.sum(1, num2: 2))
17         
18         println(self.sum_6(number: 1, number1: 2))
19         println(self.sum_7(num1: 1, num2: 3))
20         
21     }
22 
23     override func didReceiveMemoryWarning() {
24         super.didReceiveMemoryWarning()
25     }
26     
27     // func
28     
29     func sum(num1: Int, num2: Int) ->Int {
30         return num1 + num2
31     }
32     
33     // 定义返回值为void的函数的3种办法
34     func sum_1 (num: Int) {
35         
36     }
37     
38     func sum_2 (num: Int) ->() {
39         
40     }
41     
42     func sum_3 (num: Int) ->Void {
43         
44     }
45     
46     // 无参数 注意不能省略参数括号
47     func sum_4 () ->Int {
48         return 1;
49     }
50     
51     // 返回元组
52     func sum_5 (Num: Int) ->(name: String, age:Int) {
53         return ("Alice", 24)
54     }
55     
56     // 外部参数名称
57     func sum_6 (number num:Int, number1 num2:Int) ->Int {
58         return num + num2
59     }
60     
61     // 使用# 简化外部参数
62     func sum_7 (#num1:Int, num2:Int) ->Int {
63         return num1 + num2
64     }
65     
66     // 函数默认参数
67     func sum_8 (#num:Int, name:String = "Alice") ->String {
68         return name + String(num)
69     }
70     
71     // 在带有默认参数值的参数名前加个下划线 _ ，调用函数时就不用写外部参数名
72     func sum_9 (#num:Int, _ name:String = "Alice") ->String {
73         return name + String(num)
74     }
75     
76     // append
77     func sum_10 (var name:String = "Alice", strings:String, count:Int) ->String {
78         for i in 0 ... count {
79             name += "Dylan"
80         }
81         return name
82     }
83     
84     
85 }