Cpp："->"和"."的区别

environments：gcc version 8.1.0 (x86_64-posix-seh-rev0, Built by MinGW-W64 project)

class data{

public:

　　int x;

　　data(int vx):vx(x){}

　　void msg(){}

};

// create class data instances;

data d = data(3);

data* cpt = &d;

d.msg();

cpt->msg();

typedef  struct col{

　　collection(int id, float score):cid{id},cscore{score}{}

　　int cid;

　　float cscore;

} collection;

// create struct col object

collection c{1,145.3};

cout << c.cid << endl ;

cout << c.cscore <<endl;

collection* spt = &c;

cout << spt -> cid << endl;

cout << spt-> cscore << endl;

Cpp中“.”和“->”说明：

　　1、“.”是成员运算符，用于调取成员变量和成员函数；符号“.”的左边必须是实例对象（具体对象），举例为绿色字体；

　　2、“->”是地址运算符，用于引用成员变量和成员函数；符号“->”的左边是实例对象的地址或者类名（结构名），举例为黄色字体；

　　3、等价形式：d.msg() 和 (*cpt).msg() 等价；c.cid 和 (*spt).cid；

　　4、“.”和“->”常用于“类和结构”相关操作；

　　5、结构体初始化说明：传送门

下面是具体代码：

 #include<iostream>

 using namespace std;

 class Info{

 private:
     int iage;
     int iid;

 public:
     Info(int age, int id):iage(age),iid(id){}
     void msg(){
         cout << "age = " << this->iage << "\t";
         cout << "id = " << this->iid << endl;
     }

 };

 typedef    struct Data
 {
     Data(int id, float math):did{id},dmath{math}{}
     float dmath;
     int did;
 } data;

 int main(){

     Info information = Info(, );
     Info* cpt;
     information.msg();
     cpt = &information;
     cpt -> msg();

     data d{,};
     cout <<"d.id = " << d.did << "\t";
     cout <<"d.math = " << d.dmath << endl;

     data* spt;
     spt = &d;
     cout <<"spt->id = " << spt->did << "\t";
     cout <<"spt->math = " << spt->dmath << endl;

     return ;
 }

 // result:
 // age = 30        id = 1
 // age = 30        id = 1
 // d.id = 1        d.math = 145
 // spt->id = 1     spt->math = 145