How to pass as parameter an array of pointers to structure in c

Question

I'm trying to pass an array of pointers to structure as parameter, to modify it in a function and to to print the modified value in main().

The code is:

#include "stdio.h"

typedef struct testStruct_s {
   int x;
   int y;
} testStruct;

typedef testStruct typeTab[4];

void modify(typeTab tab)
{
   printf("Before modification %d\n", tab[2].x);
   tab[2].x = 3;
   printf("Modified %d\n", tab[2].x);
}


int main()
{
   typeTab tab[4];
   tab[2]->x = 0;
   printf("First %d\n", tab[2]->x);
   modify(*tab);
   printf("Second %d\n", tab[2]->x);
   return 0;
}

And I got the following output:

First 0
Before modification 1719752944
Modify 3
Second 0

I don't know the way to get the correct value of tab[2].x in modify() and how to modify this value to print tab[2]->x = 3 after.

For what I try to do, it is required to use the typedef testStruct.

Answer 1

typeTab is already an array, so typeTab tab[4] declares an array of arrays. This means tab[2]->x is the same as tab[2][0].x, which is not what you want.

Don't add the extra dimension, then modify the access accordingly.

typeTab tab;

tab[2].x = 0;
printf("First %d\n", tab[2].x);
modify(tab);
printf("Second %d\n", tab[2].x);