设计一个准确地反映按键数字具有8位显示的电话按键显示器，该电话显示器要求具有重拨的功能，当按下重拨键时，能够显示最后一次输入的电话号码。-Accurately reflect the key to design a digital telephone with eight buttons the display shows the phone display requires a redial function, when you press the redial button, it will show the last time the entered phone number.