Syntax

Considerations

<?PHP
#####################################################################
#																	#
#    This class is provided as is, it is wrote by David Dripps and  #
#    is in verision one.  It will take two dates and return the     #
#    difference in them in days, the large date must come first     #
#    comments and suggestions and improvments can be sent to        #
#    daviddripps@accomputing.biz                                    #
#                                                                	#
#   Licensed under creative commons 								#
#	http://creativecommons.org/licenses/by/2.0/uk/					#
#   This means you must mention me on the credits of any program	#
#	or website that uses this class									#
#																	#
#####################################################################

									
class dateDiffInDays{

	 function dateDiff($largeDate, $smallDate)
	{

		$l = explode ('-', $largeDate);
		$s = explode ('-', $smallDate);
		$days;
		$months;
		$years;
	
		
		//Starting from right hand side with days
		
			if ($l[2] - $s[2] >= 0 )
				{
				//if you can subtract the day in large from small
					$days = $l[2] - $s[2];
				}

			if ($l[2] - $s[2] < 0)
			{
			//if you can't bull a month off the smaller date and carry it over
	
			$l = pullOffMonth($l);
		
			
			$days = $l[2] - $s[2];
	
			}
		
		//Moving accross to months
			if ($l[1] - $s[1] >= 0 )
				{
				//if you can subtract the month in large from small
					$months = $l[1] - $s[1];
				}

			if ($l[2] - $s[2] < 0)
			{
			//if you can't pull a year off the larger date and carry it over
	
			$l = pullOffYear($l);
	

			$months = $l[1] - $s[1];
	
			}
		
			//count the months in
			for ($count = 0; $count <= $months; $count++)
			{
				$days += daysInMonth($months);
			
				$months = $months -1;
			
			
		
			}
		
		//Finally the year
				if ($l[0] - $s[0] >= 0 )
				{
				//if you can subtract the month in large from small
					$years = $l[0] - $s[0];
				

				
					//add in years
					$days += $years * 365;
				}	


		return $days;

	}

	 function pullOffMonth($date)
	{

	
		//if not January
		if ($date [1] > 1)
		{
			//how many days are in the month before current
			$daysToAdd = daysInMonth($date[1]-1);

			//take a month off
			$date[1] = $date[1]-1;
		
		
			// add the number of days
			$date[2] = $date[2] + $daysToAdd;
		
		}
	
		// if it's january we need to pull of a year too
		if ($date [1] == 1)
		{
			//Take a year off
			$date = pullOffYear($date);
		
			//how many days are in the month before current
			$daysToAdd = daysInMonth($date[1]-1);
		
			//take a month off
			$date[1] = $date[1]-1;
		
		
			// add the number of days
			$date[2] = $date[2] + $daysToAdd;
	
		}
	
		return $date;
	
	}

	 function pullOffYear ($date)
	{
		$year = $date[0]-1;
		$month = $date[1] +12;
	
		$date[0] = $year;
		$date[1] = $month;
	
		return $date;
	
	}

	 function daysInMonth($numericValueOfMonth)
	{
		$numberOfDays;
		switch ($numericValueOfMonth) {

		case 1: $numberOfDays = 31; break; //Jan
		case 2: $numberOfDays = 28; break; //Feb
	   	case 3: $numberOfDays = 31; break; //March
	   	case 4: $numberOfDays = 30; break; //April
	   	case 5: $numberOfDays = 31; break; //May
	   	case 6: $numberOfDays = 30; break; //June
	   	case 7: $numberOfDays = 31; break; //July
	   	case 8: $numberOfDays = 31; break; //August
	   	case 9: $numberOfDays = 30; break; //September
	   	case 10: $numberOfDays = 31; break; //October
	   	case 11: $numberOfDays = 30; break; //November
	   	case 12: $numberOfDays = 31; break; //Decemeber
	   	default: $numberOfDays = 0;
		}
	
		return $numberOfDays;
	}

	function inc($num)
	{
		$number = $num +1;
		return $number;
	}
}

?>