Go面试题25

1: 下面这段代码输出什么? 为什么?

func (i int) PrintInt() {
    fmt.Println(i)
}

func main() {
    var i int = 1
    i.PrintInt()
}

A. 1
B. compilation error

2: 下面这段代码输出什么? 为什么?

type People interface {
    Speak(string) string
}

type Student struct {}

func (stu *Student) Speak(think string) (talk string) {
    if think == "speak" {
        talk = "speak"
    } else {
        talk = "hi"
    }
    return
}

func main() {
    var peo People = Student{}
    think := "speak"
    fmt.Println(peo.Speak(think))
}

A. speak
B. compilation error

参考答案及解析

1: 答案及解析: B. 基于类型创建的方法必须定义在同一个包内,上面的代码基于int类型创建了PrintInt()方法, 由于int类型和方法PrintInt()定义在不同的包内,所有编译错误.解决的方法可以定义一种新的类型:

type Myint int

func (i Myint) PrintInt() {
    fmt.Println(i)
}
func main() {
    var i Myint = 1
    i.PrintInt()
}

2: 答案及解析: B.编译错误: Student does not implement People (Speak method has pointer receiver), 值类型Student没有实现接口的Speak()方法,而是指针类型*Student实现了该方法.解决方式如下:

type People interface {
    Speak(string) string
}

type Student struct {}

func (stu *Student) Speak(think string) (talk string) {
    if think == "speak" {
        talk = "speak"
    } else {
        talk = "hi"
    }
    return
}

func main() {
    var peo People = &Student{}
    think := "speak"
    fmt.Println(peo.Speak(think))
}

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Go面试题25

Go面试题25

参考答案及解析

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