文件范围内的可变长度数组? [英] Variable-length array in file scope?
本文介绍了文件范围内的可变长度数组?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
例如我有这个代码.
#include <stdlib.h>
#include <stdio.h>
#define array_size 3
typedef struct {
int array[array_size];
} TEST;
void printout(TEST *p, int element) {
printf("element: %i\n", p->array[element]);
}
int main(void) {
TEST *p;
p = malloc(sizeof(TEST));
p->array[0] = 5;
printout(p, 0);
return 0;
}
但我想根据用户输入分配 "array_size"
.
But I'd like to assign "array_size"
based on user input.
如果我尝试这样做,编译器会说在文件范围内可变地修改了‘array_size’"
.那么,我做我想做的唯一方法是将所有内容移动到 main().. 吗?
If I try to do so, the compiler says "variably modified ‘array_size’ at file scope"
. So, am I right that the only way to do what I want is to move everything to main()..?
它工作得很好,但是将结构和函数声明
保持在文件范围内似乎很整洁.
It works just fine, but keeping structs and functions declarations
in file scope seems, you know, neat.
推荐答案
最简单的方法就是动态分配内存:
The simplest approach is to just allocate the memory dynamically:
typedef struct {
int *array;
size_t size;
} TEST;
int main() {
size_t elem_count = /* from user input */
TEST p;
p->array = malloc(elem_count * sizeof int);
if(!p->array)
return -1;
p->size = elem_count;
/* ... */
free(p->array);
}
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