初始化结构中数组的值

I have a struct which has several arrays within it. The arrays have type unsigned char[4].

我有一个结构体里面有几个数组。数组的类型为无符号字符[4]。

I can initialize each element by calling

我可以通过调用来初始化每个元素

struct->array1[0] = (unsigned char) something;
... 
struct->array1[3] = (unsigned char) something;

Just wondering if there is a way to initialize all 4 values in one line.

我想知道是否有一种方法可以在一行中初始化所有的4个值。

SOLUTION: I needed to create a temporary array with all the values initialized, then call memset() to copy the values to the struct array.

解决方案:我需要创建一个初始化了所有值的临时数组，然后调用memset()将值复制到struct数组。

6 个解决方案

#1

If the values are the same, you might do something like

如果值是相同的，您可以做类似的事情

struct->array[0] = struct->array[1] = struct->array[2] = struct->array[3] = (unsigned char) something;

Otherwise, if the values are stored in an array, you can use the memcpy function like so

否则，如果值存储在数组中，可以像这样使用memcpy函数

memcpy(struct->array, some_array, sizeof(struct->array));

#2

If you really mean "initialize" in the sense that you can do it at the time you declare the variable, then sure:

如果你真正的意思是“初始化”，你可以在声明变量的时候进行，那么请确保:

struct x {
  unsigned char array1[4];
  unsigned char array2[4];
};

struct x mystruct = { 
   { 1, 2, 3, 4 },
   { 5, 6, 7, 8 }
};

#3

When you create the struct, you can initialise it with aggregate initialisation:

当您创建结构体时，您可以使用聚合初始化来初始化它:

struct test {
    int blah;
    char arr[4];
};

struct test = { 5, { 'a', 'b', 'c', 'd' } };

#4

Yes:

是的:

struct Foo
{
    unsigned char a[4];
    unsigned char b[4];
};

struct Foo x = { { 1, 2, 3, 'a' },  { 'a', 'b', 'c', 0 } };

#5

I see you have a pointer (do you?).

我看到你有一个指针(是吗?)

If you allocate memory for the pointer with calloc() everything inside the struct will be initialized with 0.

如果使用calloc()为指针分配内存，则结构体中的所有内容都将初始化为0。

Otherwise you need to memset() to 0 or assign a value element-by-element.

否则，需要将memset()赋值为0或按元素分配值。

memset(struct_pointer, 0, sizeof *struct_pointer);

#6

You can loop too:

你也可以循环:

  for(i = 0; i < 4; i++) the_struct->array1[i] = (unsigned char) something;

This will work even when you have not char but e.g. int (and values != 0). In fact, memsetting to, say, 1 a struct made of int (when sizeof int greater than 1) is not the correct way to initialize them.

即使没有char，它也可以工作，例如int(和值!= 0)。

#1