void setup()
{
  volatile char *dirf,*outf;
  volatile char *dirk,*outk;
  volatile char *dira,*outa;
  volatile char *dirc,*outc;
  dirf=0x30; outf=0x31;
  dirk=0x107; outk=0x108;
  dira=0x21; outa=0x22;
  dirc=0x27; outc=0x28;
  *dirf=0xFF; *dirk=0xFF;
  *dira=0xFF; *dirc=0xFF;
  volatile long arr[]={0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,0x7F,0x6F};
  volatile long i=0,j=0,k=0,l,m,repeat=1;
  while(1)
  {
    if(repeat==4)// for continuous loop running
    repeat=1;
    for(i=0;i<=9;i++)//to display first digit
    {
      for(j=0;j<=9;j++)//to display second digit
      {
        for(k=0;k<=9;k++)//to display third digit
        {
          for(l=0;l<=9;l++)//to display fourth digit
          {
            if(repeat==1)//for one complete loop
            {
              *outf=arr[i]+128;
              *outk=arr[j];
              *outa=arr[k];
              *outc=arr[l];
              for(m=0;m<=50000;m++);//delay
            }
            else if(repeat==2)// for second time while loop
            {
              *outf=arr[i+1];
              *outk=arr[j]+128;
              *outa=arr[k];
              *outc=arr[l];
              for(m=0;m<=5000;m++);//delay
            }
            else// for third time while loop
            {
              *outf=arr[i+1];
              *outk=arr[j];
              *outa=arr[k]+128;
              *outc=arr[l];
              for(m=0;m<=5000;m++);//delay
            }
          }
        }
      }
    }
  }
  repeat++;
}

void loop()
{
  
}