将两个升序链表合并为一个新的升序链表并输出 c语言

以下是将两个升序链表合并为一个新的升序链表的C语言代码：

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

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

struct ListNode* mergeTwoLists(struct ListNode* l1, struct ListNode* l2){
    struct ListNode *head = (struct ListNode*)malloc(sizeof(struct ListNode));
    struct ListNode *cur = head;
    while (l1 && l2) {
        if (l1->val <= l2->val) {
            cur->next = l1;
            l1 = l1->next;
        } else {
            cur->next = l2;
            l2 = l2->next;
        }
        cur = cur->next;
    }
    cur->next = l1 ? l1 : l2;
    return head->next;
}

int main() {
    // 创建链表1
    struct ListNode *l1 = (struct ListNode*)malloc(sizeof(struct ListNode));
    l1->val = 1;
    l1->next = (struct ListNode*)malloc(sizeof(struct ListNode));
    l1->next->val = 2;
    l1->next->next = (struct ListNode*)malloc(sizeof(struct ListNode));
    l1->next->next->val = 4;
    l1->next->next->next = NULL;

    // 创建链表2
    struct ListNode *l2 = (struct ListNode*)malloc(sizeof(struct ListNode));
    l2->val = 1;
    l2->next = (struct ListNode*)malloc(sizeof(struct ListNode));
    l2->next->val = 3;
    l2->next->next = (struct ListNode*)malloc(sizeof(struct ListNode));
    l2->next->next->val = 4;
    l2->next->next->next = NULL;

    // 合并链表
    struct ListNode *result = mergeTwoLists(l1, l2);

    // 输出结果
    while (result) {
        printf("%d ", result->val);
        result = result->next;
    }
    printf("\n");

    return 0;
}

输出结果为：1 1 2 3 4 4