用C语言做完整的学生管理系统

实现一个完整的学生管理系统需要以下模块：

1. 学生信息管理模块：包括学生信息的录入、修改、删除、查找和显示等功能。
2. 成绩管理模块：包括成绩的录入、修改、删除、查找和显示等功能。
3. 排名管理模块：包括对学生成绩进行排名和显示排名信息等功能。
4. 统计管理模块：包括对学生总人数、男女人数、平均成绩等信息进行统计和显示等功能。

下面是一个简单的示例代码：

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

#define MAX_STUDENT_NUM 100

typedef struct student {
    char name[20];
    char id[10];
    int gender; // 0 for male, 1 for female
    float score;
} Student;

Student students[MAX_STUDENT_NUM];
int student_count = 0;

void add_student() {
    if (student_count >= MAX_STUDENT_NUM) {
        printf("Too many students!\n");
        return;
    }

    Student s;
    printf("Input name: ");
    scanf("%s", s.name);
    printf("Input id: ");
    scanf("%s", s.id);
    printf("Input gender (0 for male, 1 for female): ");
    scanf("%d", &s.gender);
    printf("Input score: ");
    scanf("%f", &s.score);

    students[student_count++] = s;

    printf("Add student successfully!\n");
}

void modify_student() {
    char id[10];
    printf("Input id of the student to modify: ");
    scanf("%s", id);

    for (int i = 0; i < student_count; i++) {
        if (strcmp(students[i].id, id) == 0) {
            printf("Input new name: ");
            scanf("%s", students[i].name);
            printf("Input new gender (0 for male, 1 for female): ");
            scanf("%d", &students[i].gender);
            printf("Input new score: ");
            scanf("%f", &students[i].score);

            printf("Modify student successfully!\n");
            return;
        }
    }

    printf("Student not found!\n");
}

void delete_student() {
    char id[10];
    printf("Input id of the student to delete: ");
    scanf("%s", id);

    for (int i = 0; i < student_count; i++) {
        if (strcmp(students[i].id, id) == 0) {
            for (int j = i; j < student_count - 1; j++) {
                students[j] = students[j + 1];
            }
            student_count--;

            printf("Delete student successfully!\n");
            return;
        }
    }

    printf("Student not found!\n");
}

void search_student() {
    char id[10];
    printf("Input id of the student to search: ");
    scanf("%s", id);

    for (int i = 0; i < student_count; i++) {
        if (strcmp(students[i].id, id) == 0) {
            printf("Name: %s\n", students[i].name);
            printf("ID: %s\n", students[i].id);
            printf("Gender: %s\n", students[i].gender == 0 ? "Male" : "Female");
            printf("Score: %.2f\n", students[i].score);

            return;
        }
    }

    printf("Student not found!\n");
}

void show_students() {
    printf("Name\tID\tGender\tScore\n");

    for (int i = 0; i < student_count; i++) {
        printf("%s\t%s\t%s\t%.2f\n", students[i].name, students[i].id, students[i].gender == 0 ? "Male" : "Female", students[i].score);
    }
}

void rank_students() {
    Student tmp;
    for (int i = 0; i < student_count - 1; i++) {
        for (int j = i + 1; j < student_count; j++) {
            if (students[i].score < students[j].score) {
                tmp = students[i];
                students[i] = students[j];
                students[j] = tmp;
            }
        }
    }

    printf("Rank\tName\tID\tGender\tScore\n");

    for (int i = 0; i < student_count; i++) {
        printf("%d\t%s\t%s\t%s\t%.2f\n", i + 1, students[i].name, students[i].id, students[i].gender == 0 ? "Male" : "Female", students[i].score);
    }
}

void statistics() {
    int male_count = 0;
    int female_count = 0;
    float total_score = 0;

    for (int i = 0; i < student_count; i++) {
        if (students[i].gender == 0) {
            male_count++;
        } else {
            female_count++;
        }

        total_score += students[i].score;
    }

    printf("Total student count: %d\n", student_count);
    printf("Male count: %d\n", male_count);
    printf("Female count: %d\n", female_count);
    printf("Average score: %.2f\n", total_score / student_count);
}

int main() {
    int choice = -1;

    while (choice != 0) {
        printf("\n");
        printf("1. Add student\n");
        printf("2. Modify student\n");
        printf("3. Delete student\n");
        printf("4. Search student\n");
        printf("5. Show students\n");
        printf("6. Rank students\n");
        printf("7. Statistics\n");
        printf("0. Exit\n");
        printf("Input your choice: ");
        scanf("%d", &choice);

        switch (choice) {
            case 1:
                add_student();
                break;
            case 2:
                modify_student();
                break;
            case 3:
                delete_student();
                break;
            case 4:
                search_student();
                break;
            case 5:
                show_students();
                break;
            case 6:
                rank_students();
                break;
            case 7:
                statistics();
                break;
            case 0:
                printf("Goodbye!\n");
                break;
            default:
                printf("Invalid choice!\n");
                break;
        }
    }

    return 0;
}

这只是一个简单的示例，实际的学生管理系统还需要更多的功能和优化，比如支持存储到文件、导入导出数据、密码保护等等。