設計壹段單片機c程序。實現技術功能。從0到9999，壹位數時前面三位不顯

#include<reg51.h>

#define uchar unsigned char

uchar tab[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x00};? //0到9

uchar num,nn=0;

uchar led[]={10,10,10,0};

unsigned int dat=0;

sbit key=P1^0;

bit flag=0;

void t0isr() interrupt 1

{

TH0=(65536-5000)/256;

TL0=(65536-5000)%256;

switch(num)

{

case 0:P2=0x01;break;

case 1:P2=0x02;break;

case 2:P2=0x04;break;

case 3:P2=0x08;break;

default:break;

}

P0=~tab[led[num]];

num++;

num&=0x03;

}

void t1isr() interrupt 3

{

TH1=(65536-50000)/256;

TL1=(65536-50000)%256;

nn++;

nn%=5;

if(nn==0)dat++;

if(dat>9999)dat=0;

led[0]=dat/1000;

led[1]=(dat%1000)/100;

led[2]=(dat%100)/10;

led[3]=dat%10;

if(dat<1000)led[0]=10;

if(dat<100)led[1]=10;

if(dat<10)led[2]=10;

}

main()

{

TMOD=0x11;

TH0=(65536-5000)/256;

TL0=(65536-5000)%256;

TH1=(65536-50000)/256;

TL1=(65536-50000)%256;

ET1=1;

TR0=1;

ET0=1;

EA=1;

while(1)

{

if(key==0)

{

while(key==0);

TR1=~TR1;

}

}

}