合并两个有序链表

#include <iostream>

using namespace std;

class List
{
public:
    int data;
    List *next;
};

void create(List *L)
{
    List *p = new List;
    cin >> p->data;
    while (p->data != 0)
    {
        p->next = NULL;
        L->next = p;
        L = L->next;
        p = new List;
        cin >> p->data;
    }
    p->next = NULL;
}

List* merge(List* L1, List* L2)
{
    if (L1 == NULL)
        return L2;
    else if (L2 == NULL)
        return L1;
    List* pMerge = NULL;
    if (L1->data<L2->data)
    {
        pMerge = L1;
        pMerge->next = merge(L1->next, L2);
    }
    else
    {
        pMerge = L2;
        pMerge->next = merge(L1, L2->next);
    }
    return pMerge;
}

void show(List *L)
{
    List* p = L->next;
    while (p)
    {
        cout << p->data << " ";
        p = p->next;
    }
    cout << endl;
}


int main()
{
    List* L1 = new List;
    List* L2 = new List;
    List* lMerge = new List;
    L1->next = NULL;
    L2->next = NULL;
    lMerge = NULL;
    create(L1);
    show(L1);
    create(L2);
    show(L2);
    lMerge = merge(L1, L2);
    show(lMerge);
    return 0;
}