Shulou(Shulou.com)06/01 Report--

This article mainly introduces the relevant knowledge of "is the Go language an object-oriented language?". The editor shows you the operation process through an actual case. The operation method is simple, fast and practical. I hope this article "is the Go language an object-oriented language" can help you solve the problem.

1. Is Go an object oriented language?

How to use the method of Go in [introduction to Go language Series] (7)? The concept of method has been introduced in this article, but this method is not actually an object-oriented method. A method is actually a new behavior that the user adds to its defined type, and it is actually a function.

The answer to this question is in the official document:

Yes and no. Although Go has types and methods and allows an object-oriented style of programming, there is no type hierarchy. The concept of "interface" in Go provides a different approach that we believe is easy to use and in some ways more general. There are also ways to embed types in other types to provide something analogous-but not identical-to subclassing. Moreover, methods in Go are more general than in C++ or Java: they can be defined for any sort of data, even built-in types such as plain, "unboxed" integers. They are not restricted to structs (classes).

Also, the lack of a type hierarchy makes "objects" in Go feel much more lightweight than in languages such as C++ or Java.

Yes and no. Although Go has types and methods and allows object-oriented programming, it has no type hierarchy. The concept of "interface" in Go provides a different approach, and we believe it is easy to use and more general in some ways. There are also ways to embed types in other types to provide similar (rather than identical) things for subclassing. In addition, the methods in Go are more generic than those in C++ or Java: they can be defined as any kind of data. Even built-in types such as ordinary "unboxed" integers. They are not limited by structures (classes).

In addition, the lack of a type hierarchy makes "objects" in Go feel more lightweight than C++ or Java.

With this answer, the concepts of inheritance and rewriting described below are not strictly object-oriented concepts of inheritance and rewriting. Only these two nouns are borrowed here to denote the two features of Go.

2. "inheritance"

In object-oriented, inheritance is the relationship between the subclass and the parent class, and the subclass inherits the public member variables and member methods of the parent class.

As mentioned earlier, Go allows object-oriented programming. So how does Go "inherit"?

2.1. Inheritance field

In the article [introduction to Go language] (5) the use of pointers and structures, anonymous fields (also known as embedded fields) are introduced:

Package mainimport "fmt" type people struct {name string age int} type student struct {people school string} func (s student) say () {fmt.Printf ("I am% s, this year% d years old, go to school in% s." , s.name, s.age, s.school)} func main () {stu: = student {people {"Row View", 1}, "Sunshine Primary School"} stu.say ()}

Run:

I am Xing Xiaoguan. I am 1 year old this year. I am studying in Sunshine Primary School.

There is an anonymous field people in the structure student, so student has the name and age fields of people. When an anonymous field is a structure, all fields of that structure are introduced into the current structure. Is this a lot like inheritance in object-oriented? The subclass inherits the public member variables of the parent class.

Consider the following question: if there are name fields in both student and people, how does the Go language handle access?

Package mainimport "fmt" type people struct {name string / / person name age int} type student struct {people name string / / Student name school string} func main () {stu: = student {people {"Li er Gou", 1}, "Li Qian", "Sunshine School"} fmt.Println (stu.name) / / Li Qian fmt.Println (stu.people.name) / / Li er Gou}

A field conflict occurs, and Go accesses the outer field first. For example, stu.name is Li Qianqian (outer layer) and stu.people.name is Li Ergu (inner layer).

2.2. Inheritance method

We bind the function to the structure type through the receiver. Such a function is called a method, and the method belongs to the corresponding structure of the receiver conceptually.

The above achieves the effect of "inheriting" fields through anonymous fields in the structure, as well as for methods. Here is an example:

Package mainimport "fmt" type people struct {name string age int} type student struct {people school string} type programmer struct {people language string} func (p people) say () {fmt.Printf ("I am% s, this year% d years old, learn Go language with me! \ n ", p.name, p.age)} func main () {stu: = student {" Xingxiaoguan ", 1}," Sunshine Primary School "} stu.say () prom: = programmer {people {" Zhang San ", 1}," Blue Sky Construction Co., Ltd. "} prom.say ()}

Run:

I am Xing Xiaoguan. I am 1 year old this year. Learn Go language with me. I am Zhang San. I am 1 year old. Learn Go language with me.

The receiver of the say () method is of type people, while both the structure student and programmer have an anonymous field people, so both stu and prom can call the say () method. Is this a lot like a public method in which a subclass inherits a parent class in an object-oriented language?

3. Rewrite 3.1. Rewrite field

You have already described what to do if the structure conflicts with the field that is the structure of its field. With this feature, we can "rewrite" the field.

Package mainimport "fmt" type people struct {name string / / nickname age int} type student struct {people name string / / school string} func (s student) say () {fmt.Printf ("I am% s, this year% d years old, learn Go language with me! \ n ", s.name, s.age)} func main () {stu: = student {people {" Li er Dou ", 1}," Li Qian "," Sunshine Primary School "} stu.say ()}

Run:

I am Li Qian. I am 1 year old this year. Learn Go language with me.

Li er Dog is the milk name, Li Qian is the big name. When I introduced myself, I was talking about the big name Li Qian. If you need a milk name, use stu.people.name.

3.2. "rewrite" method

Here is an example:

Package mainimport "fmt" type people struct {name string age int} type student struct {people school string} type programmer struct {people language string} func (p people) say () {/ / people say method fmt.Printf ("I am% s, this year% d years old, learn the Go language with me! \ n ", p.name, p.age)} func (s student) say () {/ / student rewrites the say method fmt.Printf of people (" I am% s, I am a student, I am% d years old this year, and I go to school in% s! \ n ", s.name, s.age, s.school)} func (p programmer) say () {/ / programmer rewrites people's say method fmt.Printf (" I am% s, I am a programmer, and I am% d years old this year, I use% s language! \ n ", p.name, p.age, p.language)} func main () {stu: = student {people {" Li Qian ", 1}," Sunshine Primary School "} stu.say () prmger: = programmer {people {" Zhang San ", 1}," Go "} prmger.say ()}

Run:

I am Li Qian, a student. I am 1 year old this year. I am studying in Sunshine Primary School! I am Zhang San, I am a programmer, I am 1 year old, I use GE language!

Student and programmer "inherited" the say () method of people, but it was not appropriate, so they each "overridden" the say () method.

See here, you can understand the meaning of those two sentences in the official document.

"although Go has types and methods and allows object-oriented programming, it has no type hierarchy."

"the lack of type hierarchy also makes" objects "in Go feel more lightweight than C++ or Java."

This is the end of the introduction to "is Go an object-oriented language?" Thank you for your reading. If you want to know more about the industry, you can follow the industry information channel. The editor will update different knowledge points for you every day.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.