请按上述要求输出对应的C语言代码，并且要求修改后可以输出修改后的值

好的，以下是基于分块查找算法的C语言代码：

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

#define BLOCK_SIZE 10 //每块的大小
#define MAX_BLOCKS 100 //最大块数

typedef struct {
    int id; //学号
    char name[20]; //姓名
    char course[20]; //课程名称
    int score; //成绩
} Student;

typedef struct {
    int block_size; //每块的大小
    int block_num; //块的数量
    Student *data[MAX_BLOCKS]; //学生情况表
} BlockList;

//初始化块
void init_block(BlockList *list) {
    list->block_size = BLOCK_SIZE;
    list->block_num = 0;
}

//创建学生情况表
Student *create_student(int id, char *name, char *course, int score) {
    Student *stu = (Student *)malloc(sizeof(Student));
    stu->id = id;
    strcpy(stu->name, name);
    strcpy(stu->course, course);
    stu->score = score;
    return stu;
}

//向块中插入数据
void insert_data(BlockList *list, Student *stu) {
    int block_id = list->block_num - 1; //最后一块的编号
    if (block_id < 0 || list->data[block_id] >= list->block_size) { //需要新建块
        list->data[block_id + 1] = (Student *)malloc(list->block_size * sizeof(Student));
        block_id++;
        list->block_num++;
    }
    list->data[block_id][list->data[block_id][0].id + 1] = *stu; //插入数据
    list->data[block_id][0].id++; //更新该块中的数据数量
}

//对每一块进行排序
void sort_block(BlockList *list) {
    for (int i = 0; i < list->block_num; i++) {
        for (int j = 1; j <= list->data[i][0].id; j++) {
            for (int k = j + 1; k <= list->data[i][0].id; k++) {
                if (list->data[i][j].id > list->data[i][k].id) {
                    Student temp = list->data[i][j];
                    list->data[i][j] = list->data[i][k];
                    list->data[i][k] = temp;
                }
            }
        }
    }
}

//二分查找块的位置
int search_block(BlockList *list, int id) {
    int left = 0, right = list->block_num - 1;
    while (left <= right) {
        int mid = (left + right) / 2;
        if (list->data[mid][1].id <= id && list->data[mid][list->data[mid][0].id].id >= id) { //找到块
            return mid;
        } else if (list->data[mid][1].id > id) { //在左侧继续查找
            right = mid - 1;
        } else { //在右侧继续查找
            left = mid + 1;
        }
    }
    return -1; //未找到
}

//顺序查找结点
Student *search_node(BlockList *list, int id, char *course) {
    int block_id = search_block(list, id);
    if (block_id == -1) {
        return NULL;
    }
    for (int i = 1; i <= list->data[block_id][0].id; i++) {
        if (list->data[block_id][i].id == id && strcmp(list->data[block_id][i].course, course) == 0) {
            return &list->data[block_id][i];
        }
    }
    return NULL;
}

//修改结点
void modify_node(BlockList *list, int id, char *course, int score) {
    Student *stu = search_node(list, id, course);
    if (stu != NULL) {
        stu->score = score;
    }
}

int main() {
    BlockList list;
    init_block(&list);

    //插入数据
    insert_data(&list, create_student(1001, "John", "Math", 85));
    insert_data(&list, create_student(1002, "Mary", "Math", 90));
    insert_data(&list, create_student(1003, "Tom", "Math", 78));
    insert_data(&list, create_student(1004, "Jim", "Math", 92));
    insert_data(&list, create_student(1005, "Lucy", "Math", 87));
    sort_block(&list);

    //修改结点
    int id = 1003;
    char course[20] = "Math";
    int score = 80;
    modify_node(&list, id, course, score);

    //输出修改后的值
    Student *stu = search_node(&list, id, course);
    if (stu != NULL) {
        printf("id:%d 名字:%s 课程:%s 成绩:%d\n", stu->id, stu->name, stu->course, stu->score);
    } else {
        printf("未找到该结点\n");
    }

    return 0;
}

在这个代码中，我们首先定义了一个结构体Student，用来存储学生的信息。然后，我们定义了一个BlockList结构体，用来存储分块查找算法中的块信息。在main函数中，我们先插入了一些数据，并对每一块进行了排序。然后，我们通过调用search_node和modify_node函数来查找和修改结点。最后，我们输出修改后的值。

希望这个代码能够帮助你理解分块查找算法的实现过程！