Detailed explanation of the difference between . and -> in C language

-> The former is a pointer, and the former is a structure variable

The a->bfirst meaning is (*a).b, so they are different, but indeed ->can implemented with and* without a single operator. .Well, I'm saying that modern standardized C semantics ->can be implemented *with .a combination of and .

Early C had semantics that differed from modern C for a while.

Students who have a little knowledge of assembly may know that from the perspective of machine code and assembly, there are no variables, no such things as struct, only registers and a large array called memory.

Struct variables use . to access the members of the structure as follows:

#include<stdio.h>
#include <malloc.h>
struct stu{
	int  age;
	stu* next;
};
int main(){
	stu s1;
    s1.age =18;
	
	return 0;
}

A pointer to a structure uses -> to access the members of the structure it points to, such as:

#include<stdio.h>
#include <malloc.h>
struct stu{
	int  age;
	stu* next;
};
int main(){
	stu *phead = (stu*)malloc(sizeof(stu));//测试代码 
    phead->age=18;
	phead->next = NULL;
	stu* p = phead;
	
	return 0;
}

To put it simply: 
1. A->a means that A is a pointer to a structure 
2. Aa means that A is a structure 
3. A->a is equivalent to (*A).a

4. For AB, A is an object or structure;

5. For A->B, A is a pointer, -> is member extraction, A->B is to extract member B in A, and A can only be a pointer to a class, structure, or union;

6. (*a).b is equivalent to a->b. "." is generally read as "of"; "->" is generally read as "of the structure pointed to". That is to say, in the structure, operator -> is the combination of operator * and operator.

7. "->" is a member operator pointing to a structure. "." is a breakpoint symbol, not an operator.

8. "->" points to the first address of the structure or object. "." points to a structure or an object.

9. The purpose of "->" is to use a pointer to access the members of the structure or object. The use of "." is to use a pointer to access a structure or object.