用C语言编译已有a,b两个链表，每个链表中的结点包括学号、成绩。要求把两个链表合并，按照学号升序排列

以下是用C语言编写的合并两个链表，并按照学号升序排列的代码：

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

struct Node {
    int num;
    int score;
    struct Node* next;
};

struct Node* merge(struct Node* head1, struct Node* head2) {
    struct Node* p1 = head1;
    struct Node* p2 = head2;
    struct Node* newHead = NULL;
    struct Node* tail = NULL;

    while (p1 != NULL && p2 != NULL) {
        struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
        if (p1->num < p2->num) {
            newNode->num = p1->num;
            newNode->score = p1->score;
            p1 = p1->next;
        } else {
            newNode->num = p2->num;
            newNode->score = p2->score;
            p2 = p2->next;
        }

        newNode->next = NULL;
        if (newHead == NULL) {
            newHead = newNode;
            tail = newNode;
        } else {
            tail->next = newNode;
            tail = newNode;
        }
    }

    while (p1 != NULL) {
        struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
        newNode->num = p1->num;
        newNode->score = p1->score;
        newNode->next = NULL;

        tail->next = newNode;
        tail = newNode;
        p1 = p1->next;
    }

    while (p2 != NULL) {
        struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
        newNode->num = p2->num;
        newNode->score = p2->score;
        newNode->next = NULL;

        tail->next = newNode;
        tail = newNode;
        p2 = p2->next;
    }

    return newHead;
}

int main() {
    // 创建链表1
    struct Node* head1 = (struct Node*)malloc(sizeof(struct Node));
    struct Node* node1_1 = (struct Node*)malloc(sizeof(struct Node));
    struct Node* node1_2 = (struct Node*)malloc(sizeof(struct Node));
    struct Node* node1_3 = (struct Node*)malloc(sizeof(struct Node));
    head1->num = 2;
    head1->score = 90;
    node1_1->num = 4;
    node1_1->score = 80;
    node1_2->num = 6;
    node1_2->score = 70;
    node1_3->num = 8;
    node1_3->score = 85;
    head1->next = node1_1;
    node1_1->next = node1_2;
    node1_2->next = node1_3;
    node1_3->next = NULL;

    // 创建链表2
    struct Node* head2 = (struct Node*)malloc(sizeof(struct Node));
    struct Node* node2_1 = (struct Node*)malloc(sizeof(struct Node));
    struct Node* node2_2 = (struct Node*)malloc(sizeof(struct Node));
    struct Node* node2_3 = (struct Node*)malloc(sizeof(struct Node));
    head2->num = 1;
    head2->score = 95;
    node2_1->num = 3;
    node2_1->score = 88;
    node2_2->num = 5;
    node2_2->score = 75;
    node2_3->num = 7;
    node2_3->score = 92;
    head2->next = node2_1;
    node2_1->next = node2_2;
    node2_2->next = node2_3;
    node2_3->next = NULL;

    // 合并链表并排序
    struct Node* newHead = merge(head1, head2);
    struct Node* p = newHead;
    while (p != NULL) {
        printf("num=%d, score=%d\n", p->num, p->score);
        p = p->next;
    }

    return 0;
}

注：上述代码只是一种实现方式，还有其他方法可以达到同样的效果。