// another quite typical sorting algorithm implementated in this function,
// you know it
void Datastructure::quickSort(std::vector<Person>& A, unsigned int p,
    unsigned int q)
{
    unsigned int r;

    if(p < q)
    {
        r = partition(A, p,q);
        quickSort(A,p,r);
        quickSort(A,r+1,q);
    }
}

unsigned int Datastructure::partition(std::vector<Person>& A,
    unsigned int p, unsigned int q)
{
    // i integeter can be randomized, but trying to did it made me tweaking.
    // I got problem with two mixed conditions, randomizing i wasnt trivial
    unsigned int i = p;
    unsigned int j;

    // at()-functions decreases ~3 percentages 84 % -> 81 %, but safer.
    // enlistingYear is the primary to sort, when it is have a same value
    // then birthYear matters, can be called as older person, when he(or she?)
    // has born earlier (smaller value in birthYear).
    for(j=p+1; j<q; j++)
    {
        if(A.at(j).enlistingYear > A.at(p).enlistingYear ||
	 (A.at(j).birthYear >= A.at(p).birthYear && A.at(j).enlistingYear ==
	 A.at(p).enlistingYear))
        {
	    i++;

            swap(&A.at(i),&A.at(j));
        }
    }

    swap(&A.at(i),&A.at(p));

    return i;
}

void Datastructure::swap(Person *x, Person *y)
{
    // Person structure, using pointing Person and referensing temp to y
    // made the program and me crazy
    temp = *x;
    *x = *y;
    *y = temp;
}