Go language foundation ----- 05 ----- structure

One Structure related learning

go The structure of language is relatively simple to learn , Let's look at it in order .

package main

import "fmt"

//  The declarations of ordinary variables are var keyword , There is no need for var
type Student struct {
    
	id int
	name string
	sex byte
	age int
	addr string
}

func main(){
    

	// 1.  Initialization of structure 
	// 1.1  Structure ordinary variable initialization 
	// 1） Sequence initialization , Each member must be assigned 
 	var s1 Student = Student{
    1, "mm", 'm', 11, "gz"}
 	fmt.Println("s1 = ", s1)

 	// 2） Initialize members , If there is no assignment, the default value is automatically assigned according to the type 
 	s2 := Student{
    id:1, name: "gg"}
 	fmt.Println("s2 = ", s2)

 	// 1.2  Structure pointer variable initialization 
	// 1） Sequence initialization , Each member must be assigned , But we need to add &.
	var s3 *Student = &Student{
    2, "mm", 'm', 11, "gz"}
	fmt.Println("s3 = ", s3)

	// 2） Initialize members , If there is no assignment, the default value is automatically assigned according to the type 
	s4 := &Student{
    id:1, name: "hh"}
	fmt.Println("s4 = ", s4)

	// 2.  Use of structural members 
	// 2.1  Use of common variables 
	var s5 Student
	s5.id = 100
	s5.name = "hc"
	s5.sex = 'w'
	s5.age = 18
	s5.addr = "jm"
	fmt.Println("s5 = ", s5)

	// 2.2  The use of pointer variables 
	// go Pointer calls in member variables are all points of use (.),p.id and (*p).id It's exactly the same , non-existent C Of ->
	var s6 Student
	var p *Student
	p = &s6
	p.id = 11
	(*p).name = "lqq"
	p.sex = 'w'
	p.age = 24
	p.addr = "where"
	fmt.Println("s6 = ", s6)

	// 3.  Comparison and assignment of structures 
	// 3.1  Structure comparison 
	var s7 Student = Student{
    id: 1, name: "q", sex: 'w', age: 12, addr: "aa"}
	var s8 Student = Student{
    id: 1, name: "q", sex: 'w', age: 12, addr: "aa"}
	var s9 Student = Student{
    id: 2, name: "q", sex: 'w', age: 12, addr: "aa"}
	fmt.Println("s7==s8", s7 == s8)
	fmt.Println("s7==s9", s7 == s9)

	// 3.2  Structure assignment 
	var t Student
	t = s7
	fmt.Println("t = ", t)
	fmt.Println("t == s7", t == s7)

	// 4.  Structure as function parameter 
	// 1） Structure as function parameter is value transfer .
	// 2） Structure pointer as function parameter is address passing .  Similar to arrays .

	// 5. go The visibility of language 
	// 5.1 go and C++ Dissimilarity , No, private、protected、public These keywords .
	//  Its visibility is determined by case , When calling functions of other packages 、 Type of structure 、 Structure member variables ,
	//  Their initials should be capitalized , Otherwise, an error will be reported .
}

result ：