[avrgcc] How can I save 23 into address 00 ?

      unsigned char alarm_hour;
                                   alarm_hour++;
				   
				   if (alarm_hour >= 23)
				   {
					   alarm_hour = 0;
				   }
				   
				   
				   uint8_t ByteOfData ;
				   ByteOfData = alarm_hour ;
				   eeprom_update_byte (( uint8_t *) 00, ByteOfData );

			  case SET_ALARM_HOUR: //Set alarm hour
			  //set hour alarm
			  lcd_xy(0,0);//put on 0,0
			  lcd_string("SET HOUR ALARM ");
			  lcd_cmd(0xC0);
			  lcd_string(alarm_hour);
			  lcd_string("  ");
			  button_input = button_is_pressed();//read button
			  
			  if (button_input==1)
			  {
				  tone(50);
				  _delay_ms(50);
				  tone(0);
				  state_var = DISPLAY_TIME;
			  }
			  
			   if (button_input==2) // //  if button 2 pressed ( button up)
			   {
				   alarm_hour++;
				   tone(50);
				   _delay_ms(50);
				   tone(0);
				   if (alarm_hour >= 23)
				   {
					   alarm_hour = 0;
				   }
				   
				   
				   
				   eeprom_update_byte (( uint8_t *) 00, alarm_hour );
				   state_var = SET_ALARM_HOUR;
			   }
			   
			    if (button_input==3) // //  if button 3 pressed ( button up)
			    {
				    tone(50);
				    _delay_ms(50);
				    tone(0);
				    state_var = BATTERY_STATUS;
			    }
			  
			  break;