小型学籍管理系统C语言代码实现

以下是一个简单的小型学籍管理系统的C语言代码实现，使用了文件存储学生信息：

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

#define MAX_STUDENT_NUM 50
#define MAX_NAME_LEN 20

typedef struct {
    int id;
    char name[MAX_NAME_LEN];
    int age;
    char grade[MAX_NAME_LEN];
} Student;

void print_menu();
int add_student(Student students[], int student_num);
void print_student(Student student);
void print_students(Student students[], int student_num);
void save_students(Student students[], int student_num);
int load_students(Student students[]);

int main() {
    Student students[MAX_STUDENT_NUM];
    int student_num = load_students(students);
    char choice;

    do {
        print_menu();
        scanf(" %c", &choice);

        switch (choice) {
            case '1':
                student_num = add_student(students, student_num);
                break;
            case '2':
                print_students(students, student_num);
                break;
            case '3':
                save_students(students, student_num);
                break;
            case '0':
                printf("退出程序！\n");
                break;
            default:
                printf("输入有误，请重新输入！\n");
                break;
        }
    } while (choice != '0');

    return 0;
}

void print_menu() {
    printf("欢迎使用学籍管理系统！\n");
    printf("1. 添加学生\n");
    printf("2. 查看学生\n");
    printf("3. 保存学生信息\n");
    printf("0. 退出程序\n");
    printf("请输入操作编号：");
}

int add_student(Student students[], int student_num) {
    if (student_num >= MAX_STUDENT_NUM) {
        printf("学生信息已满！\n");
        return student_num;
    }

    Student student;
    printf("请输入学生ID：");
    scanf("%d", &student.id);

    printf("请输入学生姓名：");
    scanf("%s", student.name);

    printf("请输入学生年龄：");
    scanf("%d", &student.age);

    printf("请输入学生年级：");
    scanf("%s", student.grade);

    students[student_num] = student;
    printf("添加学生成功！\n");
    return student_num + 1;
}

void print_student(Student student) {
    printf("ID：%d，姓名：%s，年龄：%d，年级：%s\n", student.id, student.name, student.age, student.grade);
}

void print_students(Student students[], int student_num) {
    if (student_num == 0) {
        printf("学生信息为空！\n");
        return;
    }

    printf("学生信息如下：\n");

    for (int i = 0; i < student_num; i++) {
        print_student(students[i]);
    }
}

void save_students(Student students[], int student_num) {
    FILE *fp;

    fp = fopen("students.txt", "w");

    for (int i = 0; i < student_num; i++) {
        fprintf(fp, "%d %s %d %s\n", students[i].id, students[i].name, students[i].age, students[i].grade);
    }

    fclose(fp);

    printf("学生信息已保存到文件！\n");
}

int load_students(Student students[]) {
    FILE *fp;
    int student_num = 0;

    fp = fopen("students.txt", "r");

    if (fp == NULL) {
        printf("无法打开文件！\n");
        return 0;
    }

    while (!feof(fp)) {
        Student student;
        fscanf(fp, "%d%s%d%s", &student.id, student.name, &student.age, student.grade);
        students[student_num] = student;
        student_num++;
    }

    fclose(fp);

    printf("学生信息已从文件加载！\n");
    return student_num;
}

这个代码实现使用了结构体存储学生信息，实现了添加学生、查看学生、保存学生信息和从文件加载学生信息等功能。在程序启动时，会从文件中加载学生信息，如果文件不存在，则会创建一个空的学生列表。当用户选择保存学生信息时，学生信息会被保存到文件中。