#include<reg51.h>#define uchar unsigned char#define uint unsigned intsbit BEEP=P3^7;sbit K1=P1^4;sbit K2=P1^5;sbit K3=P1^6;sbit K4=P1^7;
void DelayMS(uint x){ uchar t; while(x--)for(t=0;t<120;t++);}
void Play(uchar t){uchar i;for(i=0;i<100;i++){ BEEP=~BEEP; DelayMS(t);} BEEP=0;}void main(){ if(K1==0) Play(1); if(K2==0) Play(2); if(K3==0) Play(3); if(K4==0) Play(4);