在C结构数组 [英] Array of structs in C

问题描述

我试图创建结构的数组，也是一个指针数组。我不知道该数组多大将是，所以它应该是动态的。我将结构看起来是这样的：

  typedef结构_stats_t
{
 INT小时[24]; INT numPostsInHour;
 INT天[7]; INT numPostsInDay;
 INT周[20]; INT numPostsInWeek;
 INT totNumLinesInPosts;
 INT numPostsAnalyzed;} stats_t;
 

...我需要有这些结构的每个文件（金额不详），我将分析的多。我不知道如何做到这一点。我不喜欢因为数组的大小限以下办法：

 ＃定义MAX 10
typedef结构_stats_t
{
 INT小时[24]; INT numPostsInHour;
 INT天[7]; INT numPostsInDay;
 INT周[20]; INT numPostsInWeek;
 INT totNumLinesInPosts;
 INT numPostsAnalyzed;} stats_t [MAX];
 

所以，我将如何创建这个数组？此外，将一个指向该数组将如下呢？

  stats_t统计[];
stats_t * statsPtr =安培;统计[0];
 

解决方案

这是它是如何做的，通常：

  INT N =＆LT;需要的元素＆GT的数量;
stats_t * PTR =的malloc（N * sizeof的（stats_t））;
 

然后，以填充它，

 为（INT J = 0; J＆LT; N ++ j）条
{
   PTR [J] .hours =什么
   PTR [J] .days =什么
   ...
}
 

I'm trying to create an array of structs and also a pointer to that array. I don't know how large the array is going to be, so it should be dynamic. My struct would look something like this:

typedef struct _stats_t
{
 int hours[24]; int numPostsInHour;
 int days[7]; int numPostsInDay;
 int weeks[20]; int numPostsInWeek;
 int totNumLinesInPosts;
 int numPostsAnalyzed;

} stats_t;

... and I need to have multiple of these structs for each file (unknown amount) that I will analyze. I'm not sure how to do this. I don't like the following approach because of the limit of the size of the array:

# define MAX 10
typedef struct _stats_t
{
 int hours[24]; int numPostsInHour;
 int days[7]; int numPostsInDay;
 int weeks[20]; int numPostsInWeek;
 int totNumLinesInPosts;
 int numPostsAnalyzed;

} stats_t[MAX];

So how would I create this array? Also, would a pointer to this array would look something this?

stats_t stats[];
stats_t *statsPtr = &stats[0];

解决方案

This is how it is usually done:

int n = <number of elements needed>
stats_t *ptr = malloc (n * sizeof (stats_t));

Then, to fill it in,

for (int j = 0;  j < n;  ++j)
{
   ptr [j] .hours = whatever
   ptr [j] .days = whatever
   ...
}

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