object, classes and moustaches

[wright67uk]

Im exploring the world of classes, methods and objects and im after some explanation to my code below;

 

1) what does  echo $oTime->sTime;  do in this code.

2) why do i NOT need to add "$sTime =" before "$oTime->ShowFutureDate(20); " for the code to execute properly (as i did in line

 

time.php

<?php
include('class_time.php');  
//include file where class is stored

$oTime = new Time;  
// VARIABLE = new CLASSNAME  $oTime is now the object variable

$sTime = $oTime->GenerateCurrentTime(); 
// use GenerateCurrentTime within the $oTime class 
//  -> means 'is the parent of' $oTime is the parent of ' GenerateCurrentTime()'

print 'The time is: ' . $sTime;   
// print value of GenerateCurrentTime

echo $oTime->sTime;  

echo "<br/>"; 
// new line

$oTime->ShowFutureDate(20);  
print 'The future time is: ' . $sTime; 
echo $oTime->sTime;

?>

 

class_time.php

<?php
class Time  
{         

var $stime;

  function GenerateCurrentTime() { 
       $this->sTime  = gmdate("d-m-Y H:i:s");  //assign the current date to the sTime variable
  } 
  
  function ShowFutureDate($iAddDays=0) {   
     $this->sTime  = gmdate("d-m-Y H:i:s", strtotime("+" . $iAddDays . " days"));      
  }  
} 
?>

[KevinM1]

You're confusing yourself because the class code is written in PHP 4 syntax (the var keyword).  That leads to the $sTime member variable being public, and, since you also have an $sTime local variable in play, things are getting muddled.  Use PHP 5 syntax instead:

 

class Time {
   private $sTime;
   
   function GenerateCurrentTime() { 
      $this->sTime  = gmdate("d-m-Y H:i:s");  //assign the current date to the sTime variable
   } 
  
   function ShowFutureDate($iAddDays=0) {   
      $this->sTime  = gmdate("d-m-Y H:i:s", strtotime("+" . $iAddDays . " days"));      
   }  
}

 

That might make things more clear.  Also, get this book: http://www.amazon.com/Objects-Patterns-Practice-Experts-Source/dp/143022925X/ref=sr_1_1?s=books&ie=UTF8&qid=1333840120&sr=1-1

 

Finally, -> does not mean 'parent of'.  I don't know where you got that idea, but it's wrong.  -> is the 'to member' operator, meaning that with $oTime -> GenerateCurrentTime(), you're accessing the member function/method named GenerateCurrentTime of the Time object referenced by the variable $oTime.

[ignace]

There really is no need to create your own Time object as PHP has a built-in equivalent DateTime