CodeSignal problem. I want to complete the code - arrays

Question

I have the following problem. The function printMatrix
Receive an matrix for example:
matrix:
[[0,1,1,2],
[0,5,0,0],
[2,0,3,3]]
The code that I must use is the following:
// Definition for arrays:
// typedef struct arr_##name {
// int size;
// type *arr;
// } arr_##name;
//
// arr_##name alloc_arr_##name(int len) {
// arr_##name a = {len, len > 0 ? malloc(sizeof(type) * len) : NULL};
// return a;
// }
//
//
void printMatrix(arr_arr_integer matrix)
{
}
As a clue they give me that the number of columns and rows can be determined in the following way.
int columns = matrix.arr->size; //No.columns
int rows = matrix.size; //No.rows
//Or
int columns = matrix.arr[0].size; //No.columns
int rows = matrix.size; //No.rows
My question lies in how is the rest of the code written so that the previous tracks can work?
That is, for this to work within the function printMatrix
What should you add or modify in your code for the above methods to work?
typedef struct arr_arr_integer {
int size;
type *arr;
} arr_arr_integer;
arr_arr_integer alloc_arr_arr_integer(int len) {
arr_arr_integer a = {len, len > 0 ? malloc(sizeof(type) * len) : NULL};
return a;
}
void printMatrix(arr_arr_integer matrix)
{
int columns = matrix.arr->size; //No.columns
int rows = matrix.size; //No.rows
//print matrix?
}
int main(int argc, char const *argv[])
{
//input matrix?
printMatrix(arr_arr_integer matrix)
return 0;
}
I repeat. I must use this code strictly
int columns = matrix.arr->size; //No.columns
int rows = matrix.size; //No.rows
The problem is that when I try to use those tracks I get the following compilation error.
error: request for member 'size' in something not a structure or union

Answer 1

The function alloc_arr_integer allocates a 1D array of integers.
If you need a 2D array, you'll have to call the function multiple times.
Something like:
arr_integer my2Darray[rows];
// Create the 2D array
for (int i = 0; i < rows; ++i)
{
my2Darray[i] = alloc_arr_integer(columns);
assert(my2Darray[i].arr != NULL);
}
// Initialize the 2D array
for (int i = 0; i < rows; ++i)
{
for (int j = 0; j < columns; ++j)
{
my2Darray[i].arr[j] = i * 1000 + j;
}
}
Putting it together:
int main(void)
{
int rows = 3;
int columns = 5;
arr_integer my2Darray[rows];
// Create the 2D array
for (int i = 0; i < rows; ++i)
{
my2Darray[i] = alloc_arr_integer(columns);
assert(my2Darray[i].arr != NULL);
}
//Initialize the 2D array
for (int i = 0; i < rows; ++i)
{
for (int j = 0; j < columns; ++j)
{
my2Darray[i].arr[j] = (i + 1) * 1000 + j;
}
}
for (int i = 0; i < rows; ++i)
{
for (int j = 0; j < columns; ++j)
{
printf("%d ", my2Darray[i].arr[j]);
}
printf("\n");
}
return 0;
}
OUTPUT
1000 1001 1002 1003 1004
2000 2001 2002 2003 2004
3000 3001 3002 3003 3004

Answer 2

I assume memory allocation for 'matrix' is done somewhere else.
void printMatrix(arr_arr_integer matrix)
{
int rows = matrix.size;
int columns = matrix.arr.size;
int i, j = 0;
/*print array*/
for (i = 0; i < rows; i++)
{
for (j = 0; j < columns; j++)
printf("%d ", a.arr[i].arr[j]);
printf("\n");
}
}

Answer 3

I was practicing for code signal and I wrote my own functions to stablish the arrays. They are as shown below (even though this is a little bit too late maybe).
typedef struct arr_integer
{
int size;
int *arr;
} arr_integer;
typedef struct arr_arr_integer
{
int size;
arr_integer *arr;
} arr_arr_integer;
arr_integer alloc_arr_integer(int size)
{
arr_integer *pointer;
pointer = malloc(sizeof(arr_integer));
pointer->size = size;
pointer->arr = malloc(size * sizeof(int));
return *pointer;
}
arr_arr_integer alloc_arr_arr_integer(int size)
{
arr_arr_integer *pointer;
pointer = malloc(sizeof(arr_arr_integer));
pointer->size = size;
pointer->arr = malloc(size * sizeof(arr_integer));
for (int i = 0; i < size; i++)
{
pointer->arr[i].arr = malloc(size * sizeof(int));
}
return *pointer;
}