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

#define MAX_STUDENTS 100

typedef struct {
    int id;
    char name[50];
    int score;
} Student;

int displayMenu() {
    printf("\n学生成绩管理系统\n");
    printf("1. 录入学生信息\n");
    printf("2. 显示所有学生信息\n");
    printf("3. 插入学生信息\n");
    printf("4. 删除学生信息\n");
    printf("5. 修改学生信息\n");
    printf("6. 查询学生信息\n");
    printf("7. 退出系统\n");
    printf("请选择操作: ");
    int choice;
    scanf("%d", &choice);
    return choice;
}

void addStudent(Student students[], int *count) {
    if (*count >= MAX_STUDENTS) {
        printf("学生信息已满，无法添加更多学生。\n");
        return;
    }
    printf("请输入学生ID: ");
    scanf("%d", &students[*count].id);
    printf("请输入学生姓名: ");
    scanf("%s", students[*count].name);
    printf("请输入学生成绩: ");
    scanf("%d", &students[*count].score);
    (*count)++;
    printf("学生信息录入成功。\n");
}


void displayStudents(const Student students[], int count) {
    if (count == 0) {
        printf("没有学生信息。\n");
        return;
    }
    printf("学生ID\t姓名\t成绩\n");
    for (int i = 0; i < count; i++) {
        printf("%d\t%s\t%d\n", students[i].id, students[i].name, students[i].score);
    }
}


void insertStudent(Student students[], int *count) {
    if (*count >= MAX_STUDENTS) {
        printf("学生信息已满，无法添加更多学生。\n");
        return;
    }
    Student newStudent;
    printf("请输入学生ID: ");
    scanf("%d", &newStudent.id);
    printf("请输入学生姓名: ");
    scanf("%s", newStudent.name);
    printf("请输入学生成绩: ");
    scanf("%d", &newStudent.score);

    int index = *count;
    while (index > 0 &&students[index - 1].score < newStudent.score) {
        students[index] = students[index - 1];
        index--;
    }
    students[index] = newStudent;
    (*count)++;
    printf("学生信息插入成功。\n");
}


void deleteStudent(Student students[], int *count) {
    if (*count == 0) {
        printf("没有学生信息。\n");
        return;
    }
    int id;
    printf("请输入要删除的学生ID: ");
    scanf("%d", &id);

    int index = -1;
    for (int i = 0; i < *count; i++) {
        if (students[i].id == id) {
            index = i;
            break;
        }
    }

    if (index == -1) {
        printf("未找到指定ID的学生。\n");
        return;
    }

    for (int i = index; i < *count - 1; i++) {
        students[i] = students[i + 1];
    }
    (*count)--;
    printf("学生信息删除成功。\n");
}
int compareStudents(const void *a, const void *b) {
    return ((Student *)b)->score - ((Student *)a)->score;
}
void modifyStudent(Student students[], int count) {
    if (count == 0) {
        printf("没有学生信息。\n");
        return;
    }
    int id;
    printf("请输入要修改的学生ID: ");
    scanf("%d", &id);

    int index = -1;
    for (int i = 0; i < count; i++) {
        if (students[i].id == id) {
            index = i;
            break;
        }
    }

    if (index == -1) {
        printf("未找到指定ID的学生。\n");
        return;
    }

    printf("请输入新的学生姓名: ");
    scanf("%s", students[index].name);
    printf("请输入新的学生成绩: ");
    scanf("%d", &students[index].score);
    printf("学生信息修改成功。\n");

    // 重新排序
    qsort(students, count, sizeof(Student), compareStudents);
}
void queryStudent(const Student students[], int count) {
    if (count == 0) {
        printf("没有学生信息。\n");
        return;
    }
    int id;
    printf("请输入要查询的学生ID: ");
    scanf("%d", &id);

    int found = 0;
    for (int i = 0; i < count; i++) {
        if (students[i].id == id) {
            printf("学生ID: %d, 姓名: %s, 成绩: %d\n", students[i].id, students[i].name, students[i].score);
            found = 1;
            break;
        }
    }

    if (!found) {
        printf("未找到指定ID的学生。\n");
    }
}

int main() {
    Student students[MAX_STUDENTS];
    int count = 0;
    int choice;

    do {
        choice = displayMenu();
        switch (choice) {
            case 1:
                addStudent(students, &count);
                break;
            case 2:
                displayStudents(students, count);
                break;
            case 3:
                insertStudent(students, &count);
                break;
            case 4:
                deleteStudent(students, &count);
                break;
            case 5:
                modifyStudent(students, count);
                break;
            case 6:
                queryStudent(students, count);
                break;
            case 7:
                printf("退出系统。\n");
                break;
            default:
                printf("无效的选择，请重新输入。\n");
        }
    } while (choice != 7);

    return 0;
}