Why is the implementation of a string interface in go structure a struct rather than a pointer

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Package Main//go The idea of a language combination is very heavy, between data if you want to inherit//need to combine the array in//go there is a concept of pointers, but there is no pointer operator import ("FMT") const (Animal_cat = 0animal_mouse = 1animal_dog = 2) interface of the//go language type Animal interface {name () (string) setName (name string) setType (animaltype int) GetType () ( int)}//cat type cat struct{//name m_name string "name _tag"//type M_type int "type _tag"//Kind M_spec string "kind _tag_ reflection with"}//receiver used (struct _name * structtype) and (Struct_name Structtype) are not the same//go language in the default all pass is copy//in use preference (Struct_name *structtype), avoid the value of func (cat CAT) name () (string) {return Cat.m_name}func (cat cat) SetName (name string) {Cat.m_name = Name}func (cat cat) SetType (ty int) {Cat.m_type = Ty}func (cat cat) GetType () (int) {return Cat.m_type}func (cat cat) Getspec () (string) {return cat.m_s Pec}func (Cat cat) show () {FMT. Printf (":=> name=%s type=%d spec=%s\n", Cat.m_name, Cat.m_type, Cat.m_spec)}//func (cat cat) init () {//cat.m_name = "C At "//cat.m_type = animal_cat//}//Tiger (cat branch) type tiger struct {//struct object cannot be used directly, but you can use the pointer//to aggregate a pointer of a cat object, which is equivalent to inheriting from CAT// The cat data is available, and the calling method is used directlyCat call//m_cat default is nil, all will automatically initialize M_cat * Cat}func main () {///No constructors, can construct struct to initialize cat: = cat{"Cat", Animal_cat, "Cat Spec"} Cat.show () fmt. Printf ("&cat=0x%x\n", &cat.m_name)//struct assignment operation, CAT4 and cat are two object cat4: = Catcat4.show () FMT respectively. Printf ("&cat4=0x%x\n", &cat.m_name)//If the receiver takes (Struct_name Structtype), the calling function cannot set the data for the struct///If the sink is using (struct _name* Structtype), there is no problem//go language is passed by default, not referenced, so if you want to modify the value, please wear a reference cat4.setname ("CAT1") Cat4.settype (Animal_dog) Cat4.show () cat.show ()//Use the New keyword to assign an object that is used directly when the go language initializes uninitialized data//access data. Instead of->CAT2: = new (cat) Cat2.m_name = " Mouse "Cat2.m_spec =" Mouse spec "Cat2.m_type = Animal_mousecat2.show () fmt. Printf ("&cat2=0x%x\n", CAT2)//Make assignment Operations Cat3 and CAT2 are two different pointers, but point to the same struct object cat3: = cat2fmt. Printf ("&cat3=0x%x\n", cat3) Cat3.m_name = "Mouse1" Cat3.show () Cat2.show ()}