05--swift之函数

函数定义和调用

func sayhello(name: String)->String{

return "hello,"+name+"!"

}

var r = sayhello("tom")

print(r)

//没有参数括号也必须有

func f1(){

print("f1")

}

f1()

函数带参数和返回值的几种形式

func f1(){

print("f1..")

}

func f2(age: String){

print("your age is:\(age)")

}

func f3()->Int{

return 100

}

func sum(a: Int,b: Int)->Int{

return a+b

}

func f4()->(Int,String){

return (500,"server")

}

2.函数的参数

func f2(age age1: String){

print("your age is:\(age1)")

}

f2(age: "tom")//age为外部参数，age1为内部参数

3.可变形参

func sum(numbers: Int ...)->Int{//numbers想当一个数组

var sum =  0

for e in numbers{

sum += e

}

return sum

}

var r = sum(1,2,3)

print(r)

func f1(name: String){

//name参数名默认为常量

}

//inout是输入，传递的是参数的地址

func myswap(inout a: Int, inout b: Int){

var temp = 0

temp = a

a = b

b = temp

}

var a = 1,b = 2

myswap(&a, b: &b)

print("a = \(a),b = \(b)")

4.函数的类型

func f1(name: String){

}//(string)->()

func f2(){

}//()->()

func f3(name: String)->String{

return name

}//(string)->(string)

5.函数的回调

func f1(a: (String)->()){

a("tom")

}

func f2(name: String ){

print(name)

}

f1(f2)

6.函数的嵌套

func f1(){

func f2(){

print("f2")

}

f2()

}

f1()