Golang Study of the struct

This is a creation in Article, where the information may have evolved or changed.

The general way to define a struct is as follows:

struct { field1 type1 field2 type2 ... }

type T struct {a, b int}It is also a legal grammar, which is more suitable for simple structures.

var t *T t new(T)

A variable t is a T pointer to a struct field whose value is the 0 value of the type they belong to, and uses the new function to allocate memory to a newer struct variable, which returns a pointer to the allocated memory.

Regardless of whether the variable is a struct type or a struct type pointer, the same selector character (selector-notation) is used to refer to the field of the struct, i.e.:

structint } var v myStruct    // v是结构体类型变量var p *myStruct   // p是指向一个结构体类型变量的指针v.i p.i

struct instance:

Package main Import ("FMT"    "Strings") Type personstruct{firstNamestringLastNamestring} func Upperson (P*Person ) {P.firstname=strings. ToUpper (p.firstname) p.lastname=strings. ToUpper (P.lastname)} func main () {//1-struct as a value type:    varpers1 person Pers1.firstname="Chris"Pers1.lastname="Woodward"Upperson (&pers1) fmt. Printf ("The name of the person is %s%s\n", Pers1.firstname, Pers1.lastname)//2-struct as a pointer:Pers2: =New(person) pers2.firstname="Chris"Pers2.lastname="Woodward" (*PERS2). LastName ="Woodward" //this is legal.Upperson (pers2) fmt. Printf ("The name of the person is %s%s\n", Pers2.firstname, Pers2.lastname)//3-struct as a literal:PERS3: = &person{"Chris","Woodward"} upperson (PERS3) fmt. Printf ("The name of the person is %s%s\n", Pers3.firstname, Pers3.lastname)}

Program output:

is CHRIS WOODWARD The name of the person is CHRIS WOODWARD The name of the person is CHRIS WOODWARD

Use reflection to access the tag tag of a struct:

Package main Import ("FMT"    "reflect") Type personstruct{firstNamestring' An important answer ' LastNamestring' The name of the Thing '} func main () {TT:= person{" First"," Last"}  forI: =0; I <2; i++{Reftag (TT, i)}}

Program output:

Tag:An important answer Name:firstName Tag:The name of the thing Name:lastName

To invoke a method on a value and a pointer:

You can have methods that are connected to a type, or you can have a method that connects to a type pointer.

But it doesn't matter: for type T, if there is a method on *t Meth() and it t is a variable of this type, it t.Meth() will be automatically converted to (&t).Meth() .

Both the pointer method and the value method can be called on a pointer or non-pointer, the type of the recipient is a *TwoInts method AddThem() that can be called on the value of the type TwoInts , which is automatically indirectly occurring.

two2.AddThemcan therefore be substituted (&two2).AddThem() .

Again, there are methods to inherit and overwrite in go, but it must be an anonymous field O