快速排序c++语言代码

 

int partition(int *arr, int i, int j)
{
	int tmp = arr[i];
	while (i < j)
	{
		while(i<j && arr[j] >= tmp)
		{
			--j;
		}
		arr[i] = arr[j];
		while (i<j && arr[i] <= tmp)
		{
			++i;
		}
		arr[j] = arr[i];
	}
	arr[i] = tmp;
	return i;
}

int quicksort(int *arr, int i, int j)
{
	if (i<j)
	{
		int mid = partition(arr, i, j);
		quicksort(arr, i, mid-1);
		quicksort(arr, mid+1, j);
		return 0;
	}
	else 
	{
		return -1;
	}
}

int main(int argc, char* argv[])
{
	int a[] = {4, 5, 7, 3, 1, 9, 2};
	quicksort(a, 0 , 6);
    for(int i = 0; i < 7; ++i)
	{
		cout << a[i] << " ";
	}
	cout << endl;
	return 0;
}