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* cpt = &c;

cout << cpt -> cid << endl;

cout << cpt -> 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），应用实例为绿色字体；

　　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）；

　　3、“.”和“->”常用于“类和结构”相关操作；

　　4、结构体初始化说明：传送门

下面是具体代码：

 1 #include<iostream>
 2
 3 using namespace std;
 4
 5
 6 class Info{
 7
 8 private:
 9     int iage;
10     int iid;
11
12 public:
13     Info(int age, int id):iage(age),iid(id){}
14     void msg(){
15         cout << "age = " << this->iage << "\t";
16         cout << "id = " << this->iid << endl;
17     }
18
19 };
20
21
22 typedef    struct Data
23 {
24     Data(int id, float math):did{id},dmath{math}{}
25     float dmath;
26     int did;
27 } data;
28
29
30
31 int main(){
32
33     Info information = Info(30, 1);
34     Info* cpt;
35     information.msg();
36     cpt = &information;
37     cpt -> msg();
38
39
40     data d{1,145};
41     cout <<"d.id = " << d.did << "\t";
42     cout <<"d.math = " << d.dmath << endl;
43
44     data* spt;
45     spt = &d;
46     cout <<"spt->id = " << spt->did << "\t";
47     cout <<"spt->math = " << spt->dmath << endl;
48
49     return 0;
50 }
51
52 // result:
53 // age = 30        id = 1
54 // age = 30        id = 1
55 // d.id = 1        d.math = 145
56 // spt->id = 1     spt->math = 145