Setting up Timer for Alarm system

Projects Programming
1

Hi, so i'm making a simple alarm system using arduino+buzzer+keypad+lcd
i want to make a timer for the alarm using RTC_DS1307 (as in it works for a set time of day)
what i can't figure out is how to write it correctly. i have

if (Alarmactive) {
      if (now.hour() >= Start && now.hour() <= End)

but i don't know how to add minutes and days to this statement
also i want the timer to be changeable. i have

int x, y, hour ;
      tone(BUZZ, 2000, 100);
      lcd.clear();
      lcd.setCursor(0,0);
      lcd.print("START");
      lcd.setCursor(0,1);
      key = pad.getKey();
      if (key != NO_KEY){
        if (key == '0' || key == '1' || key == '2' || key == '3' ||
            key == '4' || key == '5' || key == '6' || key == '7' ||
            key == '8' || key == '9' ) {
          hour += key;
          lcd.setCursor(x,1);
          lcd.print("*");
          x++;
        }
      }
      lcd.clear();
      lcd.setCursor(0,0);
      lcd.print("END");
      lcd.setCursor(0,1);
      if (key != NO_KEY){
        if (key == '0' || key == '1' || key == '2' || key == '3' ||
            key == '4' || key == '5' || key == '6' || key == '7' ||
            key == '8' || key == '9' ) {
          hour += key;
          lcd.setCursor(y,1);
          lcd.print("*");
          y++;
        }
      }
    }

first is this correct and second how would i add the minutes and days
Thanks

2

do you have a start.min and end.min?

why not write a sub-function that compares two time, returning a value indicating that the one time is greater than the other and testing if the current time is > than a start time and < an end time