def mark_attendance():
    cur.execute("SELECT name FROM students WHERE roll_no = ?", (roll_no,))
    row = cur.fetchone()

    status = input("Enter status (Present/Absent): ").strip().capitalize()
    today = str(date.today())

    cur.execute(
        "INSERT INTO attendance (roll_no, date, status) VALUES (?, ?, ?)",
        (roll_no, today, status)
    )

def view_attendance():
    cur.execute("SELECT date, status FROM attendance WHERE roll_no = ? ORDER BY date", (roll_no,))
    rows = cur.fetchall()

    present_count = 0
    for r in rows:
        if r[1] == "Present":
            present_count += 1

    percentage = (present_count / total) * 100