Working day calculation-Apex

When calculating working days in salesforce between two dates, we need to consider weekoff and company holidays to exclude between days.

Note: To setup organization holiday in salesforce, go to setup-->Company profile-->Holidays. view the holiday list which are already defined or click on new and enter the value for the  Holiday name,Date and select if this holiday is recuring holidday and enter appropriate value for it to create a new holiday in salesforce.

There Is a straight forward formula, which will give working days with excluding week off between two dates in below link here.
But we cannot access Holidays list of the organization using formula fiels, So we can use below apex logic  to calculate working days with excluding weekend and holidays.

public class CalculateDaysDiffExcludingHoliday {
    List<Holiday> holidayList = new List<Holiday>();
    public CalculateDaysDiffExcludingHoliday(){
        //Fetch all holiday list from the organization- you can check this from             //setup-->Company Profile-->Holidays
         holidayList=[Select StartTimeInMinutes, Name, ActivityDate From Holiday];
    }
    public integer CalculateWorkingDays(date startdt, Date enddt){
// to include both start and end date in calculation, add 1 with days //difference.
        Integer allDaysBetween = startdt.daysBetween(enddt)+1;
        system.debug('**allDaysBetween'+allDaysBetween);
        Integer allWorkingDays=0;
        //If start date and end date are same, then check is this date not fall in //holiday or weekoff
        if(startdt == enddt){
            system.debug('**startdt'+startdt+'enddt'+enddt);
            boolean isHoliday= false;
            //For excluding weekoff- week starts with Monday,As my week starts               //with sunday subtract 1 from weekstart. 
            Date weekStart = startdt.toStartofWeek().addDays(-1);
            system.debug('**weekStart'+weekStart);
           for(Holiday hDay:holidayList){
                if(startdt.daysBetween(hDay.ActivityDate) == 0){
                    isHoliday= true;
                }
            }
            if(weekStart.daysBetween(startdt) ==7 || weekStart.daysBetween(startdt) == 6){
               isHoliday= true;
            }
            system.debug('**isHoliday'+isHoliday);
            if(isHoliday == false){
                allWorkingDays = 1;
            }
        }
        else{//start date and end date are not same, so need to loop with all //dates to exclude weekoff and holiday list
            for(Integer k=0;k<allDaysBetween ;k++ ){
                if(checkifItisWorkingDay(startdt.addDays(k),holidayList)){
                    system.debug('**working day:'+startdt.addDays(k));
                    allWorkingDays++;//increment working date for each working //date.
                } 
            }
        }
        return allWorkingDays;
    }
    public boolean checkifItisWorkingDay(Date currentDate,List<Holiday> holidays){
        system.debug('**currentDate'+currentDate);
        Date weekStart = currentDate.toStartofWeek().addDays(-1);

        system.debug('**weekStart'+weekStart);
        for(Holiday hDay:holidays){
            //if date fall inholiday then return false.
            if(currentDate.daysBetween(hDay.ActivityDate) == 0){
                return false;
            }
        }
        //if date fall in weeknd return false
        if(weekStart.daysBetween(currentDate) ==7 || weekStart.daysBetween(currentDate) == 6){
            return false;
        } 
        else{//if date is not in holiday list and not in weekoff, return true to //indicate as working date.
            return true;
        }
      }
}