C结构体指针访问结构成员-创新互联

 1 #include 
 2 
 3 struct Payload {
 4   char* title;
 5   char* data;
 6 };
 7 
 8 char* extractData(struct Payload *payload);
 9 
10 int main(int argc, char const *argv[])
11 {
12   struct Payload payload;
13     
14     payload.title = "content-type";
15     payload.data = "text/html";
16 
17   char* data = extractData(&payload);
18     printf("%s
", data);
19 
20   return 0;
21 }
22 
23 
24 char* extractData(struct Payload *payload) {
25   if (NULL == payload) {
26 return 0;
27     }
28     
29   return payload->data;
30 }

#include 

struct User
{
char* name;
int age;
};
    

char* name(struct User *user) {
　　 // 传地址，访问成员需要用 ->
return user->name;
}

char* another_name(struct User *user) {
　　// 或者 dereference 后，得到结构体然后用 .
return (*(user)).name;
}

void main() {
struct User user = {"h", 11};
char* real_name = name(&user);
    printf("%s
", real_name);

    printf("================
");

char* another_real_name = another_name(&user);
    printf("%s
", another_real_name);

    printf("%zu
", sizeof(real_name));
}

指针的size 与指向位置实际存储大小无关，而是与操作系统有关，64位机器， 返回8， 32位机器返回4；