unsigned int j,k,i=0;

void main()
{ adcon1=0x06;
 trisa=1; trisb=trisd=0;
 portd=0;
  while(1)
  {
   check:
   if(porta.f1) goto car_out;
   if(porta.f0) goto go_in;
   if(porta==0) portb=0;
    goto check;
    }

go_in:

       if(portd<3)               //if there is place for parking
        {

            for(;;)
        {
        portb.f0=1; if(porta.f2) break;                          //open door B ,car out
        }
           portb.f0=0;
           portb.f1=1;
             i++;
             portd=i;
              for(j=0;j<3;j++)
           {
        // if((porta.f0)||(porta.f1)) goto check;
            delay_ms(600);     //wait for 3minut then
             }
              portb.f1=0;
           goto check;

          } else for(k=0;k<3;k++){portb.f3=1; delay_ms(200);
                                       portb.f3=0; delay_ms(200);}                   //if no place,no new car enter
   goto check;


  car_out:
       if ( portd==0 ){ goto check; }
       else
         {
          portb.f1=1;
          for(;;)
          {
             portb.f2=1; if(porta.f3) break;        //open door B ,car out
            }                                      // until sensor gives signal

            portb.f2=0; portb.f1=0;
            delay_ms(60);                       // close doorB & turn light off
            i=i-1;                                   // decrement counter
            portd=i;
            delay_ms(1500);
                  goto check; }

        }