---

with open("7.txt", "w") as f:
    f.write("Короткая строка\nОчень длинная строка для проверки работы программы\nСредняя строка\n")

with open("7.txt", "r") as f:
    lines = [line.rstrip('\n') for line in f]
    longest_line = max(lines, key=len)
    print(f"Самая длинная строка: {longest_line}")
    print(f"Количество символов: {len(longest_line)}")


with open("8.txt", "w") as f:
    f.write("Исходные данные для копирования.\nВторая строка.")

with open("8.txt", "r") as src, open("8_copy.txt", "w") as dst:
    dst.write(src.read())

print("Файл скопирован в 8_copy.txt")

with open("9.py", "w") as f:
    f.write("a = 5\nb = 10\nprint(a + b)\n")

with open("9.py", "r") as src, open("9_numbered.txt", "w") as dst:
    for num, line in enumerate(src, 1):
        dst.write(f"{num} {line}")

print("Файл 9_numbered.txt успешно создан")