使用C语言编写学生成绩管理系统

以下是一个简单的学生成绩管理系统的C语言代码：

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

#define MAX_STUDENTS 100

struct student {
    char name[20];
    int id;
    int score;
};

void add_student(struct student *students, int *num_students) {
    if (*num_students < MAX_STUDENTS) {
        struct student new_student;
        printf("Enter name: ");
        scanf("%s", new_student.name);
        printf("Enter ID: ");
        scanf("%d", &new_student.id);
        printf("Enter score: ");
        scanf("%d", &new_student.score);
        students[*num_students] = new_student;
        (*num_students)++;
        printf("Student added successfully!\n");
    } else {
        printf("Maximum number of students reached.\n");
    }
}

void remove_student(struct student *students, int *num_students) {
    int id_to_remove, i;
    printf("Enter ID of student to remove: ");
    scanf("%d", &id_to_remove);
    for (i = 0; i < *num_students; i++) {
        if (students[i].id == id_to_remove) {
            // shift all students after this one back by one
            for (; i < *num_students - 1; i++) {
                students[i] = students[i + 1];
            }
            (*num_students)--;
            printf("Student removed successfully!\n");
            return;
        }
    }
    printf("Student not found.\n");
}

void print_student(struct student student) {
    printf("%-20s %10d %10d\n", student.name, student.id, student.score);
}

void print_all_students(struct student *students, int num_students) {
    int i;
    printf("%-20s %10s %10s\n", "Name", "ID", "Score");
    for (i = 0; i < num_students; i++) {
        print_student(students[i]);
    }
}

void save_students_to_file(struct student *students, int num_students, char *filename) {
    FILE *file = fopen(filename, "w");
    if (file == NULL) {
        printf("Error opening file.\n");
        return;
    }
    int i;
    for (i = 0; i < num_students; i++) {
        fprintf(file, "%s %d %d\n", students[i].name, students[i].id, students[i].score);
    }
    fclose(file);
    printf("Students saved to file successfully!\n");
}

void load_students_from_file(struct student *students, int *num_students, char *filename) {
    FILE *file = fopen(filename, "r");
    if (file == NULL) {
        printf("Error opening file.\n");
        return;
    }
    int i = 0;
    char name[20];
    int id, score;
    while (fscanf(file, "%s %d %d\n", name, &id, &score) != EOF) {
        if (*num_students < MAX_STUDENTS) {
            struct student new_student;
            strcpy(new_student.name, name);
            new_student.id = id;
            new_student.score = score;
            students[i] = new_student;
            (*num_students)++;
            i++;
        } else {
            break;
        }
    }
    fclose(file);
    printf("Students loaded from file successfully!\n");
}

int main() {
    struct student students[MAX_STUDENTS];
    int num_students = 0;
    int choice;
    char filename[20];

    printf("Welcome to the Student Grade Management System!\n");

    while (1) {
        printf("\n");
        printf("1. Add student\n");
        printf("2. Remove student\n");
        printf("3. Print all students\n");
        printf("4. Save students to file\n");
        printf("5. Load students from file\n");
        printf("6. Exit\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);
        printf("\n");

        switch (choice) {
            case 1:
                add_student(students, &num_students);
                break;
            case 2:
                remove_student(students, &num_students);
                break;
            case 3:
                print_all_students(students, num_students);
                break;
            case 4:
                printf("Enter filename: ");
                scanf("%s", filename);
                save_students_to_file(students, num_students, filename);
                break;
            case 5:
                printf("Enter filename: ");
                scanf("%s", filename);
                load_students_from_file(students, &num_students, filename);
                break;
            case 6:
                printf("Exiting program.\n");
                exit(0);
            default:
                printf("Invalid choice.\n");
                break;
        }
    }

    return 0;
}

该程序实现了以下功能：

1. 添加学生：从用户输入中获取学生的姓名、学号和成绩，并将其添加到学生数组中。
2. 删除学生：从用户输入中获取要删除的学生的学号，然后在学生数组中查找并删除该学生。
3. 打印所有学生：按照姓名、学号和成绩的顺序打印所有学生的详细信息。
4. 将学生保存到文件：将所有学生的详细信息写入指定的文件中。
5. 从文件加载学生：从指定的文件中读取所有学生的详细信息，并将它们添加到学生数组中。
6. 退出程序：退出程序。

使用该程序，您可以轻松管理学生的成绩并将它们保存到文件中。