Question

I have a array of structs. lets call it structsarray

And i have a array of ints where the ints are index’s of the stuct. Lets call it indexarray

I would like to sort indexarray but i want to compare the sorting with an int in structsarray

Any way that can be done with that setup?

Answer 1

You have a comparison function such as this:

int my_compare(const void *a, const void *b)
{
    int index1 = *((const int *) a);
    int indexb = *((const int *) b);

    return structsarray[index1].field - structsarray[index2].field;
}

The arguments are pointer to the values in the array you are sorting. I cast the constant void pointer to a constant int pointer, and then dereference that pointer to get the actual value.