C：指针在结构定义结构体 [英] C: pointer to struct in the struct definition

问题描述

我怎么能在这个结构的定义指针指向下一个结构：

How can I have a pointer to the next struct in the definition of this struct:

typedef struct A {
  int a;
  int b;
  A*  next;
} A;

这是我第一次写的，但它不能正常工作。

this is how I first wrote it but it does not work.

推荐答案

您可以定义的typedef和远期首先声明结构在一个说明书，然后在随后的定义中定义的结构。

You can define the typedef and forward declare the struct first in one statment, and then define the struct in a subsequent definition.

typedef struct A A;

struct A
{
    int a;
    int b;
    A* next;
};

编辑：正如其他人所说，如果没有向前declaratation的结构名称仍然是结构定义（即你可以使用结构A ）内有效，但类型定义为不可用，直到typedef的定义完成后（因此使用刚 A 不会是有效）。这可能不是太大的关系只用一个指针成员，但如果你有很多的自我型指针的复杂数据结构，可能不太易于使用的。

As others have mentioned, without the forward declaratation the struct name is still valid inside the struct definition (i.e. you can used struct A), but the typedef is not available until after the typedef definition is complete (so using just A wouldn't be valid). This may not matter too much with just one pointer member, but if you have a complex data structure with lots of self-type pointers, may be less wieldy.

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