Freeing a struct of int*

Question

I have a struct which i am storing an array of integers defined as:

    typedef struct {
    int* numArr;
    int counter;
    }NumberArr;

I have initialised it to be: (int*)malloc(sizeof(int)) and reallocated when i need to add a number using: num.numArr = realloc(num.numArr, sizeof(int) * (counter+1));

I am having issue with calling free for this struct. I have tried:

   void free_data(NumberArr num) {
        for (int i = 0; i < num.counter; i++) {
            free(num.numArr[i]);
        }
        free(num.numArr);
   }

When I do this i get an error message, saying it isn't type void pointer. but i dont know what to do to make it one so I can free it.

Answer 1

This is because numArr is a single pointer (*). You just need to free it once. Your function free_date parameter should be a pointer to NumberArr, and then just pass the address of your variable like &var.

void free_data(NumberArr *num) {
    free(num->numArr);
}

The concept you are using is used while freeing double-pointer int **.