将两个递增的有序链表合并为一个递增的有序链表。要求结果链表仍用原来的存储空间，表中不允许有重复数据。C语言代码

以下是合并两个递增有序链表的C语言代码：

#include <stdio.h>
#include <stdlib.h>

typedef struct ListNode {
    int val;
    struct ListNode *next;
} ListNode;

ListNode* mergeTwoLists(ListNode* l1, ListNode* l2) {
    if (l1 == NULL) {
        return l2;
    }
    if (l2 == NULL) {
        return l1;
    }
    if (l1->val <= l2->val) {
        l1->next = mergeTwoLists(l1->next, l2);
        return l1;
    } else {
        l2->next = mergeTwoLists(l1, l2->next);
        return l2;
    }
}

int main() {
    // 创建链表1: 1 -> 3 -> 5 -> 7
    ListNode *l1 = (ListNode*)malloc(sizeof(ListNode));
    l1->val = 1;
    ListNode *node1 = (ListNode*)malloc(sizeof(ListNode));
    node1->val = 3;
    l1->next = node1;
    ListNode *node2 = (ListNode*)malloc(sizeof(ListNode));
    node2->val = 5;
    node1->next = node2;
    ListNode *node3 = (ListNode*)malloc(sizeof(ListNode));
    node3->val = 7;
    node2->next = node3;
    node3->next = NULL;

    // 创建链表2: 2 -> 4 -> 6 -> 8
    ListNode *l2 = (ListNode*)malloc(sizeof(ListNode));
    l2->val = 2;
    ListNode *node4 = (ListNode*)malloc(sizeof(ListNode));
    node4->val = 4;
    l2->next = node4;
    ListNode *node5 = (ListNode*)malloc(sizeof(ListNode));
    node5->val = 6;
    node4->next = node5;
    ListNode *node6 = (ListNode*)malloc(sizeof(ListNode));
    node6->val = 8;
    node5->next = node6;
    node6->next = NULL;

    // 合并两个链表
    ListNode *mergedList = mergeTwoLists(l1, l2);

    // 输出合并后的链表
    ListNode *p = mergedList;
    while (p != NULL) {
        printf("%d ", p->val);
        p = p->next;
    }
    printf("\n");

    return 0;
}

输出结果为：1 2 3 4 5 6 7 8