c语言实现学生成绩管理系统

学生成绩管理系统可以通过 C 语言来实现。主要需要实现以下几个功能：

1. 学生信息的录入和存储：可以定义一个结构体用来存储学生信息，包括学号、姓名、性别、出生日期等，然后通过文件操作将学生信息保存到文件中。

2. 成绩的录入和存储：同样可以定义一个结构体来存储学生的成绩信息，包括科目名称、分数等，然后将成绩信息与学生信息关联起来，保存到文件中。

3. 成绩的查询：可以根据学号或姓名等关键字查询学生的成绩信息，然后将查询结果在屏幕上输出。

4. 成绩的统计：可以统计某一门或所有科目的平均成绩、最高分、最低分等数据，并将统计结果在屏幕上输出。

下面是一个简单的学生成绩管理系统的代码示例：

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

#define MAX_STUDENT_NUM 100
#define MAX_SUBJECT_NUM 5

typedef struct {
    char id[20];  // 学号
    char name[20];  // 姓名
    char gender[10];  // 性别
    char birthdate[20];  // 出生日期
} Student;

typedef struct {
    char subject[20];  // 科目名称
    int score;  // 分数
} Score;

typedef struct {
    Student student;  // 学生信息
    Score score[MAX_SUBJECT_NUM];  // 学生的成绩信息
} Record;

Record records[MAX_STUDENT_NUM];  // 所有学生的信息和成绩数据
int num_records = 0;  // 学生数量

// 将学生信息和成绩信息保存到文件中
void save_records() {
    FILE* fp = fopen("data.txt", "w");
    if (fp == NULL) {
        printf("Failed to open file for writing.\n");
        return;
    }
    for (int i = 0; i < num_records; i++) {
        fprintf(fp, "%s %s %s %s\n", records[i].student.id, records[i].student.name,
                records[i].student.gender, records[i].student.birthdate);
        for (int j = 0; j < MAX_SUBJECT_NUM; j++) {
            if (strlen(records[i].score[j].subject) == 0) {
                break;
            }
            fprintf(fp, "%s %d ", records[i].score[j].subject, records[i].score[j].score);
        }
        fprintf(fp, "\n");
    }
    fclose(fp);
}

// 从文件中读取学生信息和成绩信息
void load_records() {
    FILE* fp = fopen("data.txt", "r");
    if (fp == NULL) {
        printf("Failed to open file for reading.\n");
        return;
    }
    while (!feof(fp)) {
        char line[1024];
        Record record;
        if (fgets(line, 1024, fp) == NULL) {
            break;
        }
        sscanf(line, "%s %s %s %s", record.student.id, record.student.name,
               record.student.gender, record.student.birthdate);
        for (int j = 0; j < MAX_SUBJECT_NUM; j++) {
            if (fscanf(fp, "%s %d", record.score[j].subject, &record.score[j].score) == 2) {
                continue;
            }
            break;
        }
        records[num_records++] = record;
    }
    fclose(fp);
}

// 添加一条学生记录
void add_record() {
    Record record;
    printf("Please input student ID: ");
    scanf("%s", record.student.id);
    printf("Please input student name: ");
    scanf("%s", record.student.name);
    printf("Please input student gender: ");
    scanf("%s", record.student.gender);
    printf("Please input student birthdate: ");
    scanf("%s", record.student.birthdate);
    for (int i = 0; i < MAX_SUBJECT_NUM; i++) {
        printf("Please input score for subject %d: ", i+1);
        scanf("%s %d", record.score[i].subject, &record.score[i].score);
        if (strlen(record.score[i].subject) == 0) {
            break;
        }
    }
    records[num_records++] = record;
    save_records();
}

// 查询学生记录
void query_record() {
    char keyword[20];
    printf("Please input the keyword to search: ");
    scanf("%s", keyword);
    printf("Results:\n");
    for (int i = 0; i < num_records; i++) {
        if (strstr(records[i].student.id, keyword) != NULL ||
            strstr(records[i].student.name, keyword) != NULL) {
            printf("Student ID: %s, Name: %s\n", records[i].student.id, records[i].student.name);
            for (int j = 0; j < MAX_SUBJECT_NUM; j++) {
                if (strlen(records[i].score[j].subject) == 0) {
                    break;
                }
                printf("Subject: %s, Score: %d\n", records[i].score[j].subject, records[i].score[j].score);
            }
        }
    }
}

// 统计成绩信息
void stat_score() {
    char subject[20];
    printf("Please input the subject to stat: ");
    scanf("%s", subject);
    int count = 0;
    int total = 0;
    int max_score = 0;
    int min_score = 100;
    for (int i = 0; i < num_records; i++) {
        for (int j = 0; j < MAX_SUBJECT_NUM; j++) {
            if (strcmp(records[i].score[j].subject, subject) == 0) {
                count++;
                total += records[i].score[j].score;
                if (records[i].score[j].score > max_score) {
                    max_score = records[i].score[j].score;
                }
                if (records[i].score[j].score < min_score) {
                    min_score = records[i].score[j].score;
                }
            }
        }
    }
    printf("Total count: %d\n", count);
    printf("Average score: %.2f\n", count > 0 ? (float)total / count : 0);
    printf("Max score: %d\n", max_score);
    printf("Min score: %d\n", min_score);
}

int main() {
    load_records();
    while (1) {
        int choice;
        printf("Please select an operation:\n");
        printf("1. Add record\n");
        printf("2. Query record\n");
        printf("3. Stat score\n");
        printf("4. Exit\n");
        printf("Your choice: ");
        scanf("%d", &choice);
        switch (choice) {
            case 1:
                add_record();
                break;
            case 2:
                query_record();
                break;
            case 3:
                stat_score();
                break;
            case 4:
                return 0;
            default:
                printf("Invalid choice.\n");
        }
    }
}

以上是一个简单的学生成绩管理系统的 C 语言代码示例，其中使用了文件操作和结构体等 C 语言的基础知识。