Dynamic array

Question

I tried to implement a dynamic array in c.

https://code.sololearn.com/cYDLAg5IhwjN/#c

Now I don't know why it doesn't print to the screen. Probably because arr->arr[i]? Is there a way to print the array using the -> operator?

Answer 1

And to add, if malloc() fails you should ideally return from the function or you will dereference a NULL pointer.

This will leak memory if realloc() fails:
arr->arr = realloc(arr->arr, arr->length * sizeof(int));

You should create a temporary variable to hold the return value of realloc() and assign it to your pointer if it successfully reallocated the memory block.

int *tmp_arr = realloc(arr->arr, arr->length * sizeof(int));
if (tmp_arr)
arr->arr = tmp_arr;

Answer 2

Robin
I know i can do it with &arr and arr.arr[i].
But I tried to use -> operator.

Now if I don't initialize the pointer with NULL it work.

It's ok if i don't initialize a pointer in situations like this?

Answer 3

Robin Gen2oo Thanks!