Code written in PHP
// PHP Gregorian date calculation algorithm based on work by Gary Katch
// http://alcor.concordia.ca/~gpkatch/gdate-algorithm.html
// http://alcor.concordia.ca/~gpkatch/gdate-c.html
function dayfromdate($year,$month,$day){
// define as floats
$m = 0.0;
$y = 0.0;
#$m = ($month + 9) % 12;
#$y = $year - $m/10;
$m = bcmod(bcadd($month,9),12);
$y = bcsub($year,(bcdiv($m,10)));
# Gregorian calendar takes the length of a year to be 365.2425 days:
# 365.0000 + 0.2500 - 0.0100 + 0.0025
# or
# 365 + 1/4 - 1/100 + 1/400 using integers
# made into a discrete function this is
# d = 365y + int(y/4) - int(y/100) + int(y/400)
// define as floats
$toreturn = 0.0;
#$toreturn = $y*365 + $y/4 - $y/100 + $y/400 + $monthoffset +$dayoffset
$toreturn = bcmul($y,365);
$toreturn = bcadd($toreturn,bcdiv($y,4));
$toreturn = bcsub($toreturn,bcdiv($y,100));
$toreturn = bcadd($toreturn,bcdiv($y,400));
# month offset
# length of months are not the same, feb is not fixed
# so we start the calendar year with March
# this makes leap days always added on to the end of the year
# and do not change day offsets for the beginning of the months
#$monthoffset = ($month*306 + 5) / 10;
$monthoffset = 0.0;
$monthoffset = bcdiv(bcadd(bcmul($m,306),5),10);
$toreturn = bcadd($toreturn,$monthoffset);
# day offset, start at zero
#$dayoffset = $day - 1;
$dayoffset = 0.0;
$dayoffset = bcsub($day,1);
$toreturn = bcadd($toreturn,$dayoffset);
return $toreturn;
}
function datediff($d1,$d2){
// this is the main function.
// takes two dates of the format YYYY-MM-DD
// and displays the difference in days between the two
// by calling 'dayfromdate', which does all the math
$date1 = split('-',$d1);
$date2 = split('-',$d2);
$year1 = $date1[0];
$month1 = $date1[1];
$day1 = $date1[2];
$year2 = $date2[0];
$month2 = $date2[1];
$day2 = $date2[2];
$res = 0.0;
$res = bcsub(dayfromdate($year1,$month1,$day1),dayfromdate($year2,$month2,$day2));
$result = (string)$res;
return "$d2 is $result days after $d1
\n";
}
function gendate(){
// generate a random gregorian date.. for testing
$year = rand(1600,3000);
$month = rand(1,12);
$day = rand(1,29);
if($month < 10){
$tm = "0".$month;
}else{
$tm = "".$month;
}
if($day < 10){
$td = "0".$day;
}else{
$td = "".$day;
}
$d1 = "$year-$tm-$td";
$d2 = array('y' => $year, 'm' => $month,'d' => $day);
return array('text-date' => $d1,'num-date' => $d2);
}
// unit test code - shows it works for arbitary Gregorian dates..
// run it from the command line to test against mysql5's datediff version
for($i<0;$i<10;$i++){
$d1 = gendate();
$d2 = gendate();
$dd = datediff($d1['text-date'],$d2['text-date']);
echo "[Datediff]" . $dd;
# change below to match your local mysql5 test account! :)
$con = mysql_connect('localhost','seo','seo');
sleep(1);
$res = mysql_query("SELECT DATEDIFF('".$d1['text-date']."','".$d2['text-date']."') as days") or die(mysql_error());
$row = mysql_fetch_array($res);
echo "[MySQL] Mysql reports actual difference is = " . $row['days'] ."
\n";
if(!bccomp($row['days'],$dd)){
echo "Doesn't add up..";
break;
}
echo "--\n";
mysql_close($con);
}
// here is an example test run, showing it is working:
#[Datediff]1710-09-02 is 455209 days after 2956-12-27
#[MySQL] Mysql reports actual difference is = 455209
#--
#[Datediff]2905-02-25 is -466866 days after 1626-12-01
#[MySQL] Mysql reports actual difference is = -466866
#--
#[Datediff]1605-10-23 is 113856 days after 1917-07-16
#[MySQL] Mysql reports actual difference is = 113856
#--
#[Datediff]2401-08-20 is 34469 days after 2496-01-03
#[MySQL] Mysql reports actual difference is = 34469
#--
#[Datediff]1863-09-16 is 16705 days after 1909-06-12
#[MySQL] Mysql reports actual difference is = 16705
#--
#[Datediff]2631-09-06 is 42712 days after 2748-08-15
#[MySQL] Mysql reports actual difference is = 42712
#--
#[Datediff]2714-08-09 is -12026 days after 2681-09-04
#[MySQL] Mysql reports actual difference is = -12026
#--
#[Datediff]1844-11-19 is 229379 days after 2472-11-25
#[MySQL] Mysql reports actual difference is = 229379
#--
#[Datediff]1640-02-11 is 464018 days after 2910-07-21
#[MySQL] Mysql reports actual difference is = 464018
#--
#[Datediff]1779-07-15 is 300513 days after 2602-04-25
#[MySQL] Mysql reports actual difference is = 300513
#--
Tower of Hanoi game.
*
* To use this class simply define the object with
* how many discs, the starting peg, the ending peg:
*
* $hanoi= new hanoi(3, 1, 3);
*
* To have the computer solve it for you:
*
* $hanoi->solve();
*
* To move things by yourself use the move function
* with parameters of the start peg and end peg. It
* will take the top disc on the start peg and move to
* the top of the end peg:
*
* $hanoi->move(0,2); // top disc from first peg to top of 3rd peg
*
* To show what discs are on what pegs:
*
* $hanoi->show();
*
* <-# Example Solution For 3 Dsics #->
*
* $hanoi->move(0, 2);
* $hanoi->move(0, 1);
* $hanoi->move(2, 1);
* $hanoi->move(0, 2);
* $hanoi->move(1, 0);
* $hanoi->move(1, 2);
* $hanoi->move(0, 2);
*
**********************************************/
class hanoi
{
var $discs;
var $start;
var $end;
var $remain;
var $pegs = array(array());
function __construct ($discs, $start, $end)
{
$this->discs = $discs;
$this->start = $start-1;
$this->end = $end-1;
$this->remain = (6 - $start - $end) - 1;
for($i=0;$i<$discs;$i++)
$this->peg[0][$i] = $i;
}
function check_win()
{
if(!(count($this->peg[$this->start]))
&& !(count($this->peg[$this->remain]))
&& (count($this->peg[$this->end]) == $this->discs))
{
echo "You Win!\n";
die();
}
}
function top_piece($peg)
{
$test = 0;
if(isset($this->peg[$peg]))
{
foreach($this->peg[$peg] as $value)
{
if($test<=$value)
$test = $value;
}
}
return $test;
}
function move ($start, $end)
{
$from = $this->top_piece($start);
$to = $this->top_piece($end);
if($to <= $from)
{
unset($this->peg[$start][$from]);
$this->peg[$end][$from] = $from;
echo "Moved top disc from peg $start to peg $end\n";
$this->check_win();
}
else
{
echo "Invalid Move: Cannot move top disc from peg $start to peg $end\n";
}
}
function solve ()
{
$this->solve_main($this->discs, $this->start, $this->end);
}
function solve_main($discs, $start, $end)
{
if ($discs == 1)
{
echo "Move top disc from peg $start to peg $end\n";
}
else
{
$this->solve_main(($discs-1), $start, $this->solve_remain($start, $end));
$this->solve_main(1, $start, $end);
$this->solve_main(($discs-1), $this->solve_remain($start, $end), $end);
}
}
function solve_remain($peg1, $peg2)
{
return (6 - $peg1 - $peg2);
}
function show()
{
for($i=1;$i<=3;$i++)
{
echo "Peg $i: ";
if(isset($this->peg[$i-1]))
{
foreach($this->peg[$i-1] as $value)
echo "$value ";
}
echo "\n";
}
}
}
?>
PHP >= PHP 4.0.4
float timer([float start,[int num]])
sets a start timer and outputs another timer less start to num decimals.
PHP >= PHP 4.0.6
int image_contrast( int img, int percent )
Adjusts the contrast of the image img based on the percent of percent. Percent is any number above 0. The lower the number, the darker the image will get. The higher the number, the brighter the image will get.
*Note: This function is fairly slow, so it would be best to apply the function once and save the image for further viewings.
> 16) & 0xFF;
$g = ($rgb >> 8) & 0xFF;
$b = $rgb & 0xFF;
$r = $percent > 1 ? min(floor($r * $percent), 255) : max(ceil($r * $percent), 0);
$g = $percent > 1 ? min(floor($g * $percent), 255) : max(ceil($g * $percent), 0);
$b = $percent > 1 ? min(floor($b * $percent), 255) : max(ceil($b * $percent), 0);
imagesetpixel($dest, $i, $j, imagecolorallocate($dest, $r, $g, $b));
}
}
return $dest;
}
?>
PHP >= PHP 4.0.6
int image_constraints( int img, int dimx, int dimy )
Creates a resized image with the maximum width being dimx and height dimy without distorting the image.
$dimx){
$ratio = ($dimx / $x);
$x = $ratio * $x;
$y = $ratio * $y;
$altered = true;
}
if($y > $dimy){
$ratio = ($dimy / $y);
$y = $ratio * $y;
$x = $ratio * $x;
$altered = true;
}
if(!$altered){
return $img;
}
$dest = imagecreatetruecolor($x, $y);
imagecopyresized($dest, $img, 0, 0, 0, 0, $x, $y, $xorg, $yorg);
return $dest;
}
?>
Drag and drop sortable list with persistence via php/mysql.