struct_type [1]是什么意思？

I found some code that gets the size of struct like this:

我找到了一些像这样得到struct大小的代码：

sizeof(struct struct_type[1]);

I tested and it does return the size of struct_type.

我测试过它确实返回了struct_type的大小。

And

和

sizeof(struct struct_type[2]);

returns twice the struct size.

返回结构大小的两倍。

Edit:

编辑：

struct_type is a struct, not an array:

struct_type是一个结构，而不是一个数组：

struct struct_type {
    int a;
    int b;
};

What does struct_type[1] actually mean?

struct_type [1]究竟意味着什么？

3 个解决方案

#1

Remember sizeof syntax:

记住sizeof语法：

sizeof ( typename );

Here typename is struct struct_type[N] or in more readable form struct struct_type [N] which is an array of N objects of type struct struct_type. As you know array size is the size of one element multiplied by the total number of elements.

这里typename是struct struct_type [N]或更易读的struct struct_type [N]，它是一个结构为struct struct_type的N个对象的数组。如您所知，数组大小是一个元素的大小乘以元素的总数。

#2

Just like:

就像：

sizeof(int[1]); // will return the size of 1 int

and

和

sizeof(int[2]); // will return the size of 2 ints

So does:

那样做：

sizeof(struct struct_type[1]); // return size of 1 `struct struct_type'

and

和

sizeof(struct struct_type[2]); // return size of 2 `struct struct_type'

Here struct struct_type[1], and struct struct_type[2] simply represent arrays of elements of type struct struct_type, and sizeof of is just returning the size of those represented arrays.

这里struct struct_type [1]和struct struct_type [2]只表示struct struct_type类型的元素数组，而sizeof只是返回那些表示数组的大小。

#3

For the declaration

为宣言

int arr[10];

size of array can be calculated by either using arr as an operand or int [10]. Since sizeof operator yields the size based on the type of operand, both sizeof(arr) and sizeof (int [10]) will return the size of array arr (ultimately arr is of type int [10]).

数组的大小可以通过使用arr作为操作数或int [10]来计算。由于sizeof运算符根据操作数的类型生成大小，因此sizeof（arr）和sizeof（int [10]）将返回数组arr的大小（最终arr的类型为int [10]）。

C11-§6.5.3.3/2:

C11-§6.5.3.3/ 2：

The sizeof operator yields the size (in bytes) of its operand, which may be an expression or the parenthesized name of a type. The size is determined from the type of the operand. The result is an integer. If the type of the operand is a variable length array type, the operand is evaluated; otherwise, the operand is not evaluated and the result is an integer constant.

sizeof运算符产生其操作数的大小（以字节为单位），该操作数可以是表达式或类型的带括号的名称。大小由操作数的类型确定。结果是整数。如果操作数的类型是可变长度数组类型，则计算操作数;否则，不评估操作数，结果是整数常量。

Similarly, for an array of struct struct_type

类似地，对于struct struct_type的数组

struct struct_type a[1];

size can be calculated either by sizeof (a) or sizeof(struct struct_type[1]).

size可以通过sizeof（a）或sizeof（struct struct_type [1]）计算。

#1