c语言 学生学籍管理系统

以下是一个简单的C语言学生学籍管理系统的实现，包括添加学生、删除学生、修改学生、查找学生、按学号排序、按年级分类显示等功能：

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

#define MAX_STUDENT_NUM 100 // 最大学生数
#define MAX_NAME_LEN 20 // 姓名最大长度
#define MAX_ID_LEN 10 // 学号最大长度
#define MAX_GRADE_LEN 10 // 年级最大长度

// 学生结构体
typedef struct {
    char name[MAX_NAME_LEN]; // 姓名
    char id[MAX_ID_LEN]; // 学号
    char grade[MAX_GRADE_LEN]; // 年级
} Student;

// 学生管理系统结构体
typedef struct {
    Student *students[MAX_STUDENT_NUM]; // 学生指针数组
    int count; // 学生人数
} StudentManager;

// 初始化学生管理系统
void init(StudentManager *manager) {
    manager->count = 0;
}

// 添加学生
void addStudent(StudentManager *manager, Student *student) {
    if (manager->count >= MAX_STUDENT_NUM) {
        printf("学生人数已达到上限，无法添加新学生！\n");
        return;
    }
    manager->students[manager->count] = student;
    manager->count++;
}

// 删除学生
void deleteStudent(StudentManager *manager, char *id) {
    int i, j;
    for (i = 0; i < manager->count; i++) {
        if (strcmp(manager->students[i]->id, id) == 0) {
            free(manager->students[i]);
            for (j = i; j < manager->count - 1; j++) {
                manager->students[j] = manager->students[j + 1];
            }
            manager->count--;
            printf("删除成功！\n");
            return;
        }
    }
    printf("学号为%s的学生不存在！\n", id);
}

// 修改学生
void modifyStudent(StudentManager *manager, char *id, Student *newStudent) {
    int i;
    for (i = 0; i < manager->count; i++) {
        if (strcmp(manager->students[i]->id, id) == 0) {
            strcpy(manager->students[i]->name, newStudent->name);
            strcpy(manager->students[i]->grade, newStudent->grade);
            printf("修改成功！\n");
            return;
        }
    }
    printf("学号为%s的学生不存在！\n", id);
}

// 查找学生
void findStudent(StudentManager *manager, char *id) {
    int i;
    for (i = 0; i < manager->count; i++) {
        if (strcmp(manager->students[i]->id, id) == 0) {
            printf("姓名：%s，学号：%s，年级：%s\n", manager->students[i]->name, manager->students[i]->id, manager->students[i]->grade);
            return;
        }
    }
    printf("学号为%s的学生不存在！\n", id);
}

// 按学号排序
void sortById(StudentManager *manager) {
    int i, j;
    Student *temp;
    for (i = 0; i < manager->count - 1; i++) {
        for (j = 0; j < manager->count - 1 - i; j++) {
            if (strcmp(manager->students[j]->id, manager->students[j + 1]->id) > 0) {
                temp = manager->students[j];
                manager->students[j] = manager->students[j + 1];
                manager->students[j + 1] = temp;
            }
        }
    }
    printf("按学号排序成功！\n");
}

// 按年级分类显示
void showByGrade(StudentManager *manager) {
    int i, j;
    char grades[MAX_STUDENT_NUM][MAX_GRADE_LEN];
    int gradeCount[MAX_STUDENT_NUM] = {0};
    int gradeNum = 0;
    for (i = 0; i < manager->count; i++) {
        for (j = 0; j < gradeNum; j++) {
            if (strcmp(manager->students[i]->grade, grades[j]) == 0) {
                gradeCount[j]++;
                break;
            }
        }
        if (j == gradeNum) {
            strcpy(grades[j], manager->students[i]->grade);
            gradeCount[j]++;
            gradeNum++;
        }
    }
    for (i = 0; i < gradeNum; i++) {
        printf("%s年级有%d名学生：\n", grades[i], gradeCount[i]);
        for (j = 0; j < manager->count; j++) {
            if (strcmp(manager->students[j]->grade, grades[i]) == 0) {
                printf("姓名：%s，学号：%s\n", manager->students[j]->name, manager->students[j]->id);
            }
        }
    }
}

// 保存到文件
void saveToFile(StudentManager *manager, char *filename) {
    FILE *fp = fopen(filename, "w");
    if (fp == NULL) {
        printf("文件打开失败！\n");
        return;
    }
    int i;
    for (i = 0; i < manager->count; i++) {
        fprintf(fp, "%s %s %s\n", manager->students[i]->name, manager->students[i]->id, manager->students[i]->grade);
    }
    fclose(fp);
    printf("保存成功！\n");
}

// 从文件读取
void readFromFile(StudentManager *manager, char *filename) {
    FILE *fp = fopen(filename, "r");
    if (fp == NULL) {
        printf("文件打开失败！\n");
        return;
    }
    char name[MAX_NAME_LEN];
    char id[MAX_ID_LEN];
    char grade[MAX_GRADE_LEN];
    while (fscanf(fp, "%s %s %s", name, id, grade) != EOF) {
        Student *student = (Student *)malloc(sizeof(Student));
        strcpy(student->name, name);
        strcpy(student->id, id);
        strcpy(student->grade, grade);
        addStudent(manager, student);
    }
    fclose(fp);
    printf("读取成功！\n");
}

// 清空数据
void clear(StudentManager *manager) {
    int i;
    for (i = 0; i < manager->count; i++) {
        free(manager->students[i]);
    }
    manager->count = 0;
    printf("清空成功！\n");
}

// 显示菜单
void showMenu() {
    printf("1.添加学生\n");
    printf("2.删除学生\n");
    printf("3.修改学生\n");
    printf("4.查找学生\n");
    printf("5.按学号排序\n");
    printf("6.按年级分类显示\n");
    printf("7.保存到文件\n");
    printf("8.从文件读取\n");
    printf("9.清空数据\n");
    printf("0.退出程序\n");
}

int main() {
    StudentManager manager;
    init(&manager);
    int choice;
    do {
        showMenu();
        printf("请输入操作编号：");
        scanf("%d", &choice);
        switch (choice) {
            case 1: {
                Student *student = (Student *)malloc(sizeof(Student));
                printf("请输入学生姓名：");
                scanf("%s", student->name);
                printf("请输入学生学号：");
                scanf("%s", student->id);
                printf("请输入学生年级：");
                scanf("%s", student->grade);
                addStudent(&manager, student);
                printf("添加成功！\n");
                break;
            }
            case 2: {
                char id[MAX_ID_LEN];
                printf("请输入要删除的学生学号：");
                scanf("%s", id);
                deleteStudent(&manager, id);
                break;
            }
            case 3: {
                char id[MAX_ID_LEN];
                printf("请输入要修改的学生学号：");
                scanf("%s", id);
                Student *newStudent = (Student *)malloc(sizeof(Student));
                printf("请输入新的学生姓名：");
                scanf("%s", newStudent->name);
                printf("请输入新的学生年级：");
                scanf("%s", newStudent->grade);
                modifyStudent(&manager, id, newStudent);
                break;
            }
            case 4: {
                char id[MAX_ID_LEN];
                printf("请输入要查找的学生学号：");
                scanf("%s", id);
                findStudent(&manager, id);
                break;
            }
            case 5: {
                sortById(&manager);
                break;
            }
            case 6: {
                showByGrade(&manager);
                break;
            }
            case 7: {
                char filename[100];
                printf("请输入文件名：");
                scanf("%s", filename);
                saveToFile(&manager, filename);
                break;
            }
            case 8: {
                char filename[100];
                printf("请输入文件名：");
                scanf("%s", filename);
                readFromFile(&manager, filename);
                break;
            }
            case 9: {
                clear(&manager);
                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;
}