void tone1()
{
     sound_play ( 659, 250 ) ;   // Frequency = 659Hz, duration = 250ms
}
void tone2() {
     sound_play ( 698, 250 ) ;   // Frequency = 698Hz, duration = 250ms
}
void Tone3() {
     sound_play ( 784, 250 ) ;   // Frequency = 784Hz, duration = 250ms
}
void melody()
{
     tone1(); tone2(); tone3(); tone3();
     tone1(); tone2(); tone3(); tone3();
     tone1(); tone2(); tone3();
     tone1(); tone2(); tone3(); tone3();
     tone1(); tone2(); tone3();
     tone3(); tone3(); tone2(); tone2(); tone1();
}

                     // main program
void main()
{
                     // variables declaration
     char m1 = 0 , m2 = 0 , m3 = 0 ;    // keypad_read variables
     char attempts = 0 ;                 // attempts variables

                      // i/p & o/p ports configuration
     trisc = 0 ; portc = 0 ;
     trisb = 0 ; portb = 0 ;
     trisd = 0xff ;
                      // lcd initialization
     lcd_init(&portb) ;
     lcd_cmd(lcd_cursor_off) ;

                        // keypad initialization
     keypad_init(&portd) ;

                         // sound play initialization
     sound_init(&portc,1) ;
     main :

     while(1)                   // endless loop
     {
     lcd_cmd(lcd_clear) ;
     lcd_out(1,1,"ENTER PASS: ") ;

     get_first_no :
                  m1 = 0 ;
                  m1 = keypad_released() ;
                  if( m1 == 0  ) goto get_first_no ;
                  if(attempts == 3)
                  {
                         lcd_out( 2,5,"ALARM ON" ) ;
                         melody() ;
                         goto main ;
                  }
                  if( m1 == 16 || m1 == 14 ) goto get_first_no ;
                  delay_ms(10) ;        // debounce time
                  lcd_chr_cp('*') ;       // lcd_print

     get_second_no :
                  m2 = 0 ;
                  m2 = keypad_released() ;
                  if( m2 == 0 || m2 == 14 ) goto get_second_no ;
                  if( m2 == 16 )
                  {
                  lcd_cmd(lcd_clear) ;
                  goto main ;
                  }
                  delay_ms(10) ;         // debounce time
                  lcd_chr_cp('*') ;       // lcd_print

     confirm :
                  m3 = 0 ;
                  m3 = keypad_released() ;
                  if( m3 == 0 || m3 != 16 ) goto confirm ;
                  delay_ms(10) ;        // debounce time


     check :
                  if( m1 == 15 && m2 == 7  )
                  {

                      lcd_out(2,5," DOOR1 ON ") ;
                      portc.f5 = 1 ; delay_ms(5000) ; portc.f5 = 0 ;
                      attempts = 0 ;
                  }
                  else if( m1 == 3 && m2 == 11  )
                  {

                       lcd_out(2,5," DOOR2 ON ") ;
                       portc.f6 = 1 ; delay_ms(5000) ; portc.f6 = 0 ;
                       attempts = 0 ;

                  }
                  else if( m1 == 11 && m2 == 3  )
                  {
                       lcd_out(2,5," DOOR3 ON ") ;
                       portc.f7 = 1 ; delay_ms(5000) ; portc.f7 = 0 ;
                       attempts = 0 ;
                  }
                  else if ( m1 == 2 && m2 == 2 )
                  {
                       lcd_out(2,5,"DOORS1&2 ON") ;
                       portc.f5 = portc.f6 =1 ; delay_ms(5000) ;
                       portc.f5 = portc.f6 = 0 ;
                       attempts = 0 ;
                  }
                  else                    // if invalid pass is entered
                  {
                       attempts++ ;

                       lcd_out(2,5,"INVALID") ;
                       while( keypad_released() == 0 ) {}

                  }

      }             // end loop
}                  // end program