[英]what does typedef struct node *NODE indicate?
struct node
{
int coef;
int exp;
struct node *link;
};
typedef struct node *NODE;
It defines NODE
as a synonym for the type struct node *
, so when you'll be declaring a variable of type NODE
you'll be actually declaring a pointer to struct node
.它将
NODE
定义为struct node *
类型的同义词,所以当你声明一个NODE
类型的变量时,你实际上是在声明一个指向struct node
的指针。
Personally, I don't think that such declaration is a good idea: you're "hiding a pointer" (which is almost always a bad idea), and, moreover, you are not highlighting this fact in any way into the new name.就个人而言,我认为这样的声明不是一个好主意:您“隐藏了一个指针”(这几乎总是一个坏主意),而且,您没有以任何方式在新名称中强调这一事实.
它使NODE
成为struct node *
的 typedef。
NODE
becomes an alias for struct node*
. NODE
成为struct node*
的别名。
EDIT: Okay, for the comment (if I write my answer as comment, it would be too long and not formatted):编辑:好的,对于评论(如果我将我的答案写为评论,它将太长且未格式化):
There's no different way to write this.没有什么不同的写法。 Here,
typedef
is used just to create a synonym/alias for pointer to struct node
.在这里,
typedef
仅用于为指向struct node
指针创建同义词/别名。
An example for usage would be:使用示例是:
void f()
{
// some code
NODE p = NULL;
// do something with p
// for example use malloc and so on
// like: p = malloc( sizeof( struct node ) );
// and access like: p->coef = ..; p->expr = ..
// do something with p and free the memory later (if malloc is used)
}
is the same as是相同的
void f()
{
// some code
struct node* p = NULL;
// do something with p
}
Using NODE
makes it just shorter (anyway, I wouldn't advise such typedef
, as you're hiding, that it's a pointer , not a struct
or other type, as mentioned in @Matteo Italia's answer).使用
NODE
使它更短(无论如何,我不会建议这样的typedef
,因为您正在隐藏,它是一个指针,而不是struct
或其他类型,如@Matteo Italia 的回答中所述)。
The format, you're referring: "typedef struct{}type_name format" is something else.您所指的格式是:“typedef struct{}type_name 格式”是另一回事。 It's kind of a trick in
C
, to avoid writing struct
keyword (as it's obligatory in C
, and NOT in C++
).这是
C
的一种技巧,以避免编写struct
关键字(因为它在C
是必需的,而不是在C++
)。 So所以
typedef struct node
{
//..
} NODE;
would make NODE
alias for struct node
.将为
struct node
制作NODE
别名。 So, the same example as above:所以,与上面相同的例子:
void f()
{
// some code
NODE p;
// do something with p
// note that now p is automatically allocated, it's real struct
// not a pointer. So you can access its members like:
// p.coef or p.expr, etc.
}
is the same as是相同的
void f()
{
// some code
struct node p;
// do something with p
}
NOTE that now, p
is NOT a pointer, it's struct node
.请注意,现在
p
不是指针,而是struct node
。
只是告诉你可以每次只使用 NODE 创建节点类型的指针,而不是每次都写 struct node *
what does
typedef struct node *NODE
indicate?typedef struct node *NODE
表示什么?
UPPERCASE IS NO GOOD大写不好
Reserve ALL UPPERCASE identifiers for MACROS .为MACROS保留所有大写标识符。
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