请用C语言编写一个学生考勤系统

好的，我可以帮您解答这个问题。以下是一个简单的学生考勤系统的 C 语言代码示例：

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

#define MAX_STUDENTS 50

struct student {
    int id;
    char name[20];
    int present;
};

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

void add_student();
void mark_attendance();
void display_attendance();

int main() {
    int choice;
    while (1) {
        printf("\n---------------------\n");
        printf("1. Add student\n");
        printf("2. Mark attendance\n");
        printf("3. Display attendance\n");
        printf("4. Exit\n");
        printf("---------------------\n\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);

        switch (choice) {
        case 1:
            add_student();
            break;
        case 2:
            mark_attendance();
            break;
        case 3:
            display_attendance();
            break;
        case 4:
            exit(0);
        default:
            printf("Invalid choice!\n");
        }
    }

    return 0;
}

void add_student() {
    if (num_students >= MAX_STUDENTS) {
        printf("Maximum students reached!\n");
        return;
    }

    struct student s;
    s.id = num_students + 1;
    printf("Enter student name: ");
    scanf("%s", s.name);
    s.present = 0;

    students[num_students++] = s;

    printf("Student added successfully!\n");
}

void mark_attendance() {
    int id;
    printf("Enter student ID: ");
    scanf("%d", &id);

    for (int i = 0; i < num_students; i++) {
        if (students[i].id == id) {
            students[i].present = 1;
            printf("Attendance marked for student '%s'!\n", students[i].name);
            return;
        }
    }

    printf("Invalid student ID!\n");
}

void display_attendance() {
    printf("ID\tName\tAttendance\n");
    printf("------------------------------\n");
    for (int i = 0; i < num_students; i++) {
        printf("%d\t%s\t", students[i].id, students[i].name);
        if (students[i].present) {
            printf("Present\n");
        } else {
            printf("Absent\n");
        }
    }
}

这个例子中，我们使用结构体存储每个学生的信息，包括 ID、姓名以及出勤情况。通过添加学生、标记出勤和显示出勤等功能来实现一个简单的学生考勤系统。