51 单片机 实现 计算器功能，通过键盘输入并且由数码管显示，由蜂鸣器判别按键音-51 MCU calculator function, through keyboard input and the digital display, touch-tone discrimination by the buzzer

运用AT89C51单片机，驱动蜂鸣器发出新年好的歌声。-Using AT89C51 microcontroller, drives the buzzer New Year good singing.