Сортировка Шелла

#include <iostream>
#include <ctime>

using namespace std;

template<typename T> void show(T *, const long);
template<typename T> void shell(T *, const long);
int sedgewick(long *, const long);

int main() {
    const long size = 12L;
    int vector[size];
    srand((unsigned)time(NULL));
    for (long n = 0; n < size; n++) vector[n] = rand();
    show(vector, size);
    cout << endl;
    shell(vector, size);
    show(vector, size);
    cin.get();
    return 0;
}

template<typename T> void show(T * _vector, const long _size) {
    for (long n = 0; n < _size; n++) cout << _vector[n] << ' ';
    cout << endl;
}

template<typename T> void shell(T * _vector, const long _size) {
    const long lim = 40;
    long sequence[lim], increment, n, m;
    int size = sedgewick(sequence, _size);

    while (size >= 0) {
        increment = sequence[size--];

        for (n = increment; n < _size; n++) {
            T temp = _vector[n];
            for (m = n - increment; (m >= 0) && (_vector[m] > temp); m -= increment)
                _vector[m + increment] = _vector[m];
            _vector[m + increment] = temp;
        }
    }
}

int sedgewick(long * _increment, const long _size) {
    unsigned long x1, x2, x3;
    x1 = x2 = x3 = 1;
    int step = -1;

    do {
        if (++step & 1) _increment[step] = 8 * x1 - 6 * x2 + 1;
        else {
            _increment[step] = 9 * x1 - 9 * x3 + 1;
            x2 *= 2;
            x3 *= 2;
        }
        x1 *= 2;
    } while (3 * _increment[step] < _size);
    return step > 0 ? --step : 0;
}