C++链表冒泡排序

#include <iostream>
using namespace std;
//别问我为什么要写链表的冒泡排序。
struct Node
{
int data;
Node *next;
Node(int d = int()) :data(d), next(NULL){}
};
class List
{
public:
List(int a[], int n)
{
first = NULL;
for (int i = 0; i < n; i++)
{
if (first == NULL)
{
first = new Node(a[i]);
}
else
{
Node *s = new Node(a[i]);
Node *p = first;
while (p->next != NULL)
{
p = p->next;
}
s->next = p->next;
p->next = s;
}
}
}
//冒泡排序
void Bul()
{
Node *ptr_one = first;
Node *ptr_twe;
Node *pr_one = NULL;
Node *save = NULL;
if (ptr_one == NULL || ptr_one->next == NULL)return;
while (ptr_one != NULL && ptr_one->next != NULL)
{
Node *pr_twe = ptr_one;
Node *m2 = NULL;
save = ptr_one;
for (ptr_twe = ptr_one->next; ptr_twe != NULL;)
{

if (ptr_one->data > ptr_twe->data)
{
if (pr_one == NULL)
{
Node *m1;
Node *a;
m1 = ptr_twe->next;
m2 = ptr_one->next;

first->next = m1;
pr_twe->next = first;
a = first;
ptr_twe->next = m2;
first = ptr_twe;

save = ptr_twe;

ptr_twe = a;
ptr_one = first;
}
else
{
Swap(pr_one, pr_twe);
save = pr_one->next;
ptr_one = save;
ptr_twe = pr_twe->next;
}
}
pr_twe = ptr_twe;
if (ptr_twe == NULL)continue;
ptr_twe = ptr_twe->next;
}
pr_one = save;

ptr_one = pr_one->next;
}
}
void Swap(Node *prv1, Node *&prv2)
{
if (prv1->next == prv2)
{
Node *m = prv1->next;
Node *n = prv2->next;
m->next = n->next;
n->next = m;
prv1->next = n;
prv2 = n;
}
else
{
Node *m1 = prv1->next;
Node *save = m1->next;
Node *m2 = prv2->next;
m1->next = m2->next;
prv2->next = m1;
m2->next = save;
prv1->next = m2;
}
}
void Printf()
{
Node *p = first;
while (p != NULL)
{
cout << p->data << "   ";
p = p->next;
}
cout << endl;
}
private:
Node *first;
};
int main()
{
int a[] = { 3, 10, 13, 102, 3, 5, 6, 1, 3, 4, 6, 7, 9, 1000, 3, 2, 4, 6, 66, 4, 3, 32, 454, 4, 99 };
List list(a, sizeof(a) / sizeof(int));
list.Bul();
list.Printf();
return 0;
}