golang(06)函数介绍

func 函数名(函数参数)返回值类型{

}

func HelloFunc(str string) string{
    return str
}

fmt.Println(Hello("Nice to meet you!"))

func Add(a int, b int) (ret int, err error) {
	if a < 0 || b < 0 {
		//不允许负数相加
		err = errors.New("should be non-negative numbers")
		return
	}
	return a + b, nil
}

res, err:=Add(100, 200) 
if err != nil{
    fmt.Println("add error !")
    return
}
fmt.Println("add result is ", res)

func myfunc() {
	i := 0
HERE:
	fmt.Println(i)
	i++
	if i < 10 {
		goto HERE
	}
}

//不定参数
func myfuncv(args ...int) {
	for _, arg := range args {
		fmt.Println(arg)
	}
}

myfuncv(1,2,4,7,8)

func myfuncv3(args ...int) {
	//按原样传递
	myfuncv(args...)
	//按切片传递
	myfuncv(args[1:]...)
}

func MyPrintf(args ...interface{}) {
	for _, arg := range args {
		//interface 任意类型，
		//arg.(type)只能用于switch结构
		switch arg.(type) {
		case int:
			fmt.Println(arg, "is an int value.")
		case string:
			fmt.Println(arg, "is a string value.")
		case int64:
			fmt.Println(arg, "is an int64 value")
		default:
			fmt.Println(arg, "is an unknown type")
		}
	}
}