用c语言写个成绩管理系统

好的，我可以为您提供一个简单的成绩管理系统的代码示例，具体实现如下：

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

#define MAX_NAME_LEN 20
#define MAX_GRADE_NUM 5

struct student {
    char name[MAX_NAME_LEN];
    int grades[MAX_GRADE_NUM];
    int grade_num;
    float average;
};

void add_student(struct student *students, int *num_students);
void print_student(struct student *students, int student_index);
void print_all_students(struct student *students, int num_students);

int main(void) {
    struct student students[100];
    int num_students = 0;
    char input;

    while (1) {
        printf("Enter 'a' to add a student, 'p' to print a student, 'l' to print all students, or 'q' to quit: ");
        scanf(" %c", &input);

        if (input == 'a') {
            add_student(students, &num_students);
        } else if (input == 'p') {
            int student_index;
            printf("Enter the index of the student to print: ");
            scanf("%d", &student_index);
            print_student(students, student_index);
        } else if (input == 'l') {
            print_all_students(students, num_students);
        } else if (input == 'q') {
            break;
        } else {
            printf("Invalid input\n");
        }
    }

    return 0;
}

void add_student(struct student *students, int *num_students) {
    if (*num_students >= 100) {
        printf("Cannot add more students\n");
        return;
    }

    struct student new_student;
    printf("Enter the name of the student: ");
    scanf("%s", new_student.name);

    printf("Enter the number of grades for the student: ");
    scanf("%d", &new_student.grade_num);

    for (int i = 0; i < new_student.grade_num; i++) {
        printf("Enter grade %d: ", i+1);
        scanf("%d", &new_student.grades[i]);
    }

    float sum = 0;
    for (int i = 0; i < new_student.grade_num; i++) {
        sum += new_student.grades[i];
    }
    new_student.average = sum / new_student.grade_num;

    students[*num_students] = new_student;
    (*num_students)++;
}

void print_student(struct student *students, int student_index) {
    if (student_index < 0 || student_index >= 100 || student_index >= MAX_NAME_LEN) {
        printf("Invalid index\n");
        return;
    }

    struct student student = students[student_index];
    printf("Name: %s\n", student.name);
    printf("Grades: ");
    for (int i = 0; i < student.grade_num; i++) {
        printf("%d ", student.grades[i]);
    }
    printf("\n");
    printf("Average: %.2f\n", student.average);
}

void print_all_students(struct student *students, int num_students) {
    for (int i = 0; i < num_students; i++) {
        printf("Student %d:\n", i+1);
        print_student(students, i);
    }
}

这个成绩管理系统可以添加学生、打印单个学生、打印全部学生信息。其中，每个学生有一个姓名、一组成绩和成绩数量，可以计算出平均分。