快速排序

#include<iostream>
using namespace std;
//快速排序
void Quicksort(int a[], int low, int high)
{
    if (low >= high)
        return;
    int first = low;
    int last = high;
    int key = a[first];
    while (first < last)
    {
        while (first < last&&a[last] >= key)
        {
            --last;
        }
        a[first] = a[last] ;
        while (first < last&&a[first] <= key)
        {
            ++first;
        }
        a[last] = a[first];
    }
    a[first] = key;
    Quicksort(a, low, first - 1);
    Quicksort(a, first + 1, high);
}
int main()
{
    int a[10];
    for (int i = 0; i < 10; i++)
        cin >> a[i];
    for (auto t : a)
        cout << t << " ";
    cout << endl;
    Quicksort(a, 0,9);// 快速排序
    for (auto t : a)
        cout << t << " ";
    cout << endl;
    system("pause");
    return 0;
}

#include<iostream>
using namespace std;
int partition(int data[], int length, int start, int end)
{
    if (data == NULL || length <= 0 || start < 0 || end >= length)
        throw new exception("Invalid Parameters");
    int index = rand() % (end - start + 1) + start;
    
    swap(data[index], data[end]);
    int small = start - 1;
    
    for (index = start; index < end; ++index)
    {
        if (data[index] < data[end])
        {

            ++small;
            if (small != index)
            {
                swap(data[index], data[small]);
            }
        }
    }
    ++small;
    swap(data[small], data[end]);
    return small;
}
void quicksort(int data[], int length, int start, int end)
{
    if (start == end)
        return;
    int index = partition(data, length, start, end);
    if (index > start)
        quicksort(data, length, start, index - 1);
    if (index < end)
        quicksort(data, length, index + 1, end);
}
int main()
{
    int data[4] = { 2, 5, 2, 3 };
    cout << partition(data, 4, 0, 3) << endl;
    /*quicksort(data, 4, 0, 3);
    for (int i = 0; i < 4; i++)
        cout << data[i] << endl;*/
    system("pause");
    return 0;
}