IR program to find the obstacles in 8051

//IR program to find the obstacles

#include<reg51.h>

#include"lcd.h"

sbit sw=P3^2;

bit flag;

void isr(void) interrupt 0

{

      flag=1;

}                      

main()

{

      EA=EX0=1;

      init_lcd();

      cmd_lcd(0x01);

      while(1)

      {

        if(flag==1)

        {

       

                      flag=0;

                      cmd_lcd(0x80);

                      str_lcd("Abstacle Detected");

                      P0=0x55;

                      delay_ms(300);

        }           

                      P0=0x00;

      }

}