链表的简单实现

#include <cstdio>
#include <cassert>

typedef struct node {
    int data;
    node * next;
}Node, *pNode;

pNode CreateList() {
    pNode head, p1, p2;
    p1 = new Node;
    printf("Please input data: \n");
    scanf("%d", &p1->data);
    int n = 0;

    while (p1->data != 0) {
        n++;
        if (n == 1)
            head = p1;
        else
            p2->next = p1;
        p2 = p1;
        p1 = new Node;
        scanf("%d", &p1->data);
    }
    p2->next = NULL;
    return head;
}

void Sort(pNode head) {
    for (pNode p = head; p != NULL; p = p->next) {
        for (pNode q = p->next; q != NULL; q = q->next) {
            if (q->data < p->data) {
                int tmp = p->data;
                p->data = q->data;
                q->data = tmp;
            }
        }
    }
}

pNode Merge(pNode head1, pNode head2) {
    assert(head1 != NULL && head2 != NULL);

    Sort(head1);
    Sort(head2);

    pNode head, end;
    bool first = true;

    while (true) {
        if (head1 == NULL) {
            end->next = head2;
            break;
        }
        else if (head2 == NULL) {
            end->next = head1;
            break;
        }
        if (head1->data >= head2->data) {
            pNode p = new Node;
            p->data = head2->data;
            head2 = head2->next;
            if (first) {
                first = false;
                head = p;
            }
            else
                end->next = p;
            end = p;
        }
        else {
            pNode p = new Node;
            p->data = head1->data;
            head1 = head1->next;
            if (first) {
                first = false;
                head = p;
            }
            else
                end->next = p;
            end = p;
        }
    }
    return head;
}

int main()
{
    pNode plist1 = CreateList();
    pNode plist2 = CreateList();

    pNode plist3 = Merge(plist1, plist2);
    for (pNode p = plist3; p != NULL; p = p->next)
        printf("%d\n", p->data);

    return 0;
}