#讀取檔案的全部內容
def get():
    f = None
    try:
        f = open('致橡樹.txt', 'r', encoding='utf-8')
        print(f.read())
    except FileNotFoundError:
        print('無法開啟指定的檔案!')
    except LookupError:
        print('指定了未知的編碼!')
    except UnicodeDecodeError:
        print('讀取檔案時解碼錯誤!')
    finally:
        if f:
            f.close()

#一行一行的讀取檔案
def line():
	# 通過for-in迴圈逐行讀取
	with open('a.txt', mode='r') as f:
		for line in f:
			print(line+"\n")
			time.sleep(0.5)
#寫入內容
def insert():
    filenames = ('a.txt', 'b.txt', 'c.txt')
    fs_list = []
    try:
        for filename in filenames:
            fs_list.append(open(filename, 'w', encoding='utf-8'))
        for number in range(1, 10000):
            if is_prime(number):
                if number < 100:
                    fs_list[0].write(str(number) + '\n')
                elif number < 1000:
                    fs_list[1].write(str(number) + '\n')
                else:
                    fs_list[2].write(str(number) + '\n')
    except IOError as ex:
        print(ex)
        print('寫檔案時發生錯誤!')
    finally:
        for fs in fs_list:
            fs.close()
    print('操作完成!')

    
if __name__ == '__main__':
    get()
    line()
    insert()