Sorting an array using multiple sort criteria (QuickSort)

Question

I am trying to find out how (using a quicksort algorithm) to sort an struct array by 2 criterias. For example say I had a struct of:

struct employee{
   char         


        

Answer 1

int compare_employee (struct employee * a, struct employee * b) {
    int diff = strcmp(a->gender, b->gender);

    if (diff) // if gender different
        return -diff; // sort descending, please double check this and reverse in case I am wrong

    return a->id - b->id; // else sort by id
}

Will output a negative number if a < b, positive if a > b, zero if they are equal.

Use it eigther in your own quicksort or as a qsort comparator.