要求用C语言编写:1.先编写一个带结构的文件，存入电脑，要求第一行从左到右的内容依次是：序号、姓名、班级、学号，每排每列对齐，没有对齐的地方用空格补齐。2.从电脑中能够读入这个带结构的文件，并进行删增改后，重新存入电脑，3.这个文件要有纵横结构，每横表示一个记录4. 编出来的代码要能够在c的运行界面进行后续的插入、删除和修改

好的，根据您的需求，我为您编写了以下C语言程序：

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

#define MAX_NAME_LEN 20
#define MAX_CLASS_LEN 20
#define MAX_ID_LEN 10
#define MAX_RECORDS 100

// 定义学生结构体
struct Student {
    int id;
    char name[MAX_NAME_LEN];
    char class[MAX_CLASS_LEN];
    char sid[MAX_ID_LEN];
};

// 定义记录结构体
struct Record {
    int id;
    char name[MAX_NAME_LEN];
    char class[MAX_CLASS_LEN];
    char sid[MAX_ID_LEN];
};

// 定义全局变量
struct Record records[MAX_RECORDS]; // 存储所有记录
int num_records; // 记录总数

// 函数声明
void read_file();
void save_file();
void print_records();
void add_record();
void delete_record();
void modify_record();

int main() {
    read_file();
    print_records();
    int choice;
    do {
        printf("请选择操作：\n");
        printf("1. 添加记录\n");
        printf("2. 删除记录\n");
        printf("3. 修改记录\n");
        printf("4. 退出\n");
        scanf("%d", &choice);
        switch (choice) {
            case 1:
                add_record();
                break;
            case 2:
                delete_record();
                break;
            case 3:
                modify_record();
                break;
            case 4:
                break;
            default:
                printf("无效的选择，请重新输入！\n");
                break;
        }
    } while (choice != 4);
    save_file();
    return 0;
}

// 从文件中读取记录
void read_file() {
    FILE *fp = fopen("students.dat", "rb");
    if (fp == NULL) {
        printf("无法打开文件！\n");
        exit(1);
    }
    fseek(fp, 0, SEEK_END);
    int file_size = ftell(fp);
    num_records = file_size / sizeof(struct Student);
    fseek(fp, 0, SEEK_SET);
    for (int i = 0; i < num_records; i++) {
        struct Student student;
        fread(&student, sizeof(struct Student), 1, fp);
        struct Record record;
        record.id = i + 1;
        strcpy(record.name, student.name);
        strcpy(record.class, student.class);
        strcpy(record.sid, student.sid);
        records[i] = record;
    }
    fclose(fp);
}

// 将记录保存到文件中
void save_file() {
    FILE *fp = fopen("students.dat", "wb");
    if (fp == NULL) {
        printf("无法打开文件！\n");
        exit(1);
    }
    for (int i = 0; i < num_records; i++) {
        struct Student student;
        strcpy(student.name, records[i].name);
        strcpy(student.class, records[i].class);
        strcpy(student.sid, records[i].sid);
        fwrite(&student, sizeof(struct Student), 1, fp);
    }
    fclose(fp);
}

// 打印所有记录
void print_records() {
    printf("序号\t姓名\t班级\t学号\n");
    for (int i = 0; i < num_records; i++) {
        printf("%d\t%s\t%s\t%s\n", records[i].id, records[i].name, records[i].class, records[i].sid);
    }
}

// 添加一条记录
void add_record() {
    if (num_records >= MAX_RECORDS) {
        printf("记录已满，无法添加！\n");
        return;
    }
    printf("请输入姓名：");
    char name[MAX_NAME_LEN];
    scanf("%s", name);
    printf("请输入班级：");
    char class[MAX_CLASS_LEN];
    scanf("%s", class);
    printf("请输入学号：");
    char sid[MAX_ID_LEN];
    scanf("%s", sid);
    struct Record record;
    record.id = num_records + 1;
    strcpy(record.name, name);
    strcpy(record.class, class);
    strcpy(record.sid, sid);
    records[num_records] = record;
    num_records++;
}

// 删除一条记录
void delete_record() {
    if (num_records == 0) {
        printf("记录为空，无法删除！\n");
        return;
    }
    printf("请输入要删除的记录的序号：");
    int id;
    scanf("%d", &id);
    if (id <= 0 || id > num_records) {
        printf("无效的序号！\n");
        return;
    }
    for (int i = id; i < num_records; i++) {
        records[i - 1] = records[i];
        records[i - 1].id = i;
    }
    num_records--;
}

// 修改一条记录
void modify_record() {
    if (num_records == 0) {
        printf("记录为空，无法修改！\n");
        return;
    }
    printf("请输入要修改的记录的序号：");
    int id;
    scanf("%d", &id);
    if (id <= 0 || id > num_records) {
        printf("无效的序号！\n");
        return;
    }
    printf("请输入姓名：");
    char name[MAX_NAME_LEN];
    scanf("%s", name);
    printf("请输入班级：");
    char class[MAX_CLASS_LEN];
    scanf("%s", class);
    printf("请输入学号：");
    char sid[MAX_ID_LEN];
    scanf("%s", sid);
    struct Record record;
    record.id = id;
    strcpy(record.name, name);
    strcpy(record.class, class);
    strcpy(record.sid, sid);
    records[id - 1] = record;
}

这个程序实现了从文件中读取记录、添加记录、删除记录、修改记录、保存记录到文件的功能，您可以根据自己的需要进行修改和完善。