51单片机编程，请求帮忙修改程序以实现功能

51单片机C程序各位大佬帮忙修改一下以实现功能:显示管从99减到00，并停留在00不断闪烁。#include unsigned char num[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f}; void delay() { unsigned int a=500; while(a--); } void main() { unsigned char i,j; while(1) { j++; if(j>100) { j=0; i--; if(i<99) i=0; } P1=num[i/10]; P3_0=0;P3_1=1; delay(); P3_0=1;P3_1=1; P1=num[i%10];P3_0=1;P3_1=0; delay(); P3_0=1;P3_1=1;

供参考：

#include<stdio.h>
unsigned char num[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f};
void delay()
{
    unsigned int a=500;
    while(a--);
}
void main()
{
    unsigned char i=99,j;
    while(1)
    {
         P1=num[i/10];
         P3_0=0;P3_1=1;
         delay();
         P3_0=1;P3_1=1;
         P1=num[i%10];
         P3_0=1;P3_1=0;
         delay();
         P3_0=1;P3_1=1;
         //....
         if(i==0){i=0;delay();delay();}
         else    i--;
    }
}