在 C 中初始化了一个指针数组 - 可变大小的 object 可能未初始化

Question

I was trying to initialise a array made by pointer:

the code I used was:

int c = 15;
Struct *Pointer[c] = {NULL};

but C give me a error message which says:

"message": "variable-sized object may not be initialized",

but when I change my code to:

Struct *Pointer[15] = {NULL};

it worked!

Is there any way to fix it? I can't use 15 instead of variable "c"

Cheers!

Answer 1

You need to make a loop to initialize the array:

for (int i = 0; i < c; i++)
    Pointer[i] = NULL; // set all of these values to NULL

Now, Pointer will be of size c .

Also, this link may help, too: Array[n] vs Array[10] - Initializing array with variable vs real number

Answer 2

Variable length arrays may not be initialized in their declarations.

You can use the standard string function memset to initialize the memory occupied by a variable length array.

For example

#include <string.h>

//...

int c = 15;
Struct *Pointer[c];

memset( Pointer, 0, c * sizeof( *Pointer ) );

Pay attention to that variable length arrays shall have automatic storage duration that is they may be declared in a function and may not have the storage specifier static .