1.多个返回值

    func x(x:Int, y:Int)->(Int, Int){
        let a = x+y
        let b = x-y
        return (a, b)
    }
    let (a, b) = x(10, y: 3)
    print("a = \(a)")
    let val = x(10, y: 3)
    print("val = \(val.0)")

2.默认参数

    func x(x:Int, y:Int=10)->(Int, Int){
        let a = x+y
        let b = x-y
        return (a, b)
    }
    x(10)
    x(10, y: 3)

3.函数参数

    z(y, x: 10, y: 7)
    
    func x(x:Int, y:Int)->(Int, Int){
        let a = x+y
        let b = x-y
        return (a, b)
    }
    
    func z(fx:(Int, Int)->(Int,Int), x:Int, y:Int){
        let x = fx(x, y).0;
        print("x = \(x)")
    }

4.关键字inout

    func change(inout m:Int){
        m = 10;
    }
    var xx = 2;
    change(&xx)
    print("xx = \(xx)")

IOS_swift_函数用法

原文：http://blog.csdn.net/zimo2013/article/details/50057233