用C语言写一个学生成绩管理系统

好的，一个简单的学生成绩管理系统可以包含以下功能：

1. 添加学生信息
2. 删除学生信息
3. 修改学生信息
4. 查询学生成绩
5. 显示所有学生信息

以下是一个使用C语言实现的示例代码：

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

#define MAX_STUDENTS 100

struct student {
    int id;
    char name[50];
    double score;
};

struct student students[MAX_STUDENTS];
int num_students = 0;

int add_student() {
    if (num_students >= MAX_STUDENTS) {
        printf("Error: too many students\n");
        return 0;
    }

    struct student s;
    printf("Enter student ID: ");
    scanf("%d", &s.id);
    printf("Enter student name: ");
    scanf("%s", s.name);
    printf("Enter student score: ");
    scanf("%lf", &s.score);

    students[num_students++] = s;
    printf("Student added successfully\n");
    return 1;
}

int find_student(int id) {
    for (int i = 0; i < num_students; i++) {
        if (students[i].id == id) {
            return i;
        }
    }
    return -1;
}

int delete_student() {
    int id;
    printf("Enter student ID to delete: ");
    scanf("%d", &id);

    int index = find_student(id);
    if (index < 0) {
        printf("Error: student not found\n");
        return 0;
    }

    for (int i = index; i < num_students - 1; i++) {
        students[i] = students[i + 1];
    }
    num_students--;

    printf("Student deleted successfully\n");
    return 1;
}

int update_student() {
    int id;
    printf("Enter student ID to update: ");
    scanf("%d", &id);

    int index = find_student(id);
    if (index < 0) {
        printf("Error: student not found\n");
        return 0;
    }

    struct student s;
    printf("Enter new student name (or press Enter to keep current name): ");
    scanf("%s", s.name);
    if (strlen(s.name) > 0) {
        strcpy(students[index].name, s.name);
    }

    printf("Enter new student score (or press Enter to keep current score): ");
    char score_input[10];
    scanf("%s", score_input);
    if (strlen(score_input) > 0) {
        sscanf(score_input, "%lf", &s.score);
        students[index].score = s.score;
    }

    printf("Student updated successfully\n");
    return 1;
}

void print_student(struct student s) {
    printf("%d\t%s\t%.2lf\n", s.id, s.name, s.score);
}

void print_all_students() {
    printf("ID\tName\tScore\n");
    for (int i = 0; i < num_students; i++) {
        print_student(students[i]);
    }
}

int main() {
    int choice = 0;
    while (choice != 6) {
        printf("\nStudent Score Management System\n");
        printf("1. Add student\n");
        printf("2. Delete student\n");
        printf("3. Update student\n");
        printf("4. Query student score\n");
        printf("5. Show all students\n");
        printf("6. Exit\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);

        switch (choice) {
            case 1: add_student(); break;
            case 2: delete_student(); break;
            case 3: update_student(); break;
            case 4:
                {
                    int id;
                    printf("Enter student ID to query: ");
                    scanf("%d", &id);

                    int index = find_student(id);
                    if (index < 0) {
                        printf("Error: student not found\n");
                    } else {
                        print_student(students[index]);
                    }
                    break;
                }
            case 5: print_all_students(); break;
            case 6: break;
            default: printf("Error: invalid choice\n"); break;
        }
    }

    return 0;
}

这个示例代码实现了一个简单的学生成绩管理系统，可以添加、删除、修改和查询学生信息，以及显示所有学生的信息。请注意，这只是一个示例，实际的学生成绩管理系统可能需要更多的功能和更复杂的算法。