A simple example of PHP object-oriented programming

<?phpdate_default_timezone_set ("PRC"); /* * 1. Static properties are used to hold the class's public data * 2. Static methods can only access static properties * 3. Static members do not need to instantiate objects to be accessible * 4. The inside of a class can access its own static members through the self or the static keyword * 5. Static members of the parent class can be accessed via the parent keyword * 6. You can access static members outside the class definition through the name of the class * */ Class human{ Public $name; protected $height; Only itself and subclasses can access Public $weight; Private $isHungry = true; Cannot access the Quilt class public static $sValue = "Static value in Human class". \ n "; Public function Eat ($food) { echo $this->name. "' S eating "." ' $food "." \ n "; } Public Function info () { echo "HUMAN:". $this->name. ";". $this->height. ";". $this->ishungry. " \ n "; } } Class animal{ } The definition of a class starts with the keyword class, followed by the name of the class, which is usually capitalized with the first letter, beginning and ending in brackets Use the extends keyword in PHP to represent the class's inheritance, followed by the class name of the parent class PHP can only follow the class name of a class after extends, which is the single-inheritance principle in PHP Class Nbaplayer extends Human { Public $name = "Jordan"; Defining properties Public $height = "198cm"; Public $weight = "98kg"; Public $team = "Bull"; Public $playernumber = "23"; Private $age = "40"; Private class members can only be accessed internally Static properties are defined by adding the static keyword after the access control keyword public static $president = "David Stern"; Static methods add the Static keyword after the access control keyword when you define it public static function Changepresident ($NEWPRESDT) { When using static members in a class definition, use the self or Static keyword followed by: operator to Note that when you access the static member property,:: After you need to follow the $ symbol Self:: $president = $NEWPRESDT; Use the parent keyword to access static members in the parent class Echo Parent:: $sValue. " \ n "; } constructor, which is called automatically when an object is instantiated function __construct ($name, $height, $weight, $team, $playernumber) { echo "in Nbaplayer constuctor\n"; $this->name = $name; $this is a pseudo-variable inside PHP that represents the object itself, and can access the properties and methods of the object in a $->this way $this->height = $height; $this->weight = $weight; $this->team = $team; $this->playernumber = $playernumber; echo $this->height. " \ n "; } Destructors, which are called automatically at the end of program execution Destructors are often used to clean up resources used by the program. For example, if the program uses a printer, you can release the printer resources in a destructor function __destruct () { echo "destroying". $this->name. " \ n "; } Defining methods Public Function Run () { echo "running\n"; } Public Function jump () { echo "jumping\n"; } Public Function Dribble () { echo "dribbling\n"; } Public Function Shoot () { echo "shooting\n"; } Public Function Dunk () { echo "dunking\n"; } Public Function Pass () { echo "passing\n"; } Public Function Getage () { echo $this->name. "' S age is ". ($this->age-2). " \ n "; } } Class-To-object instantiation The class object is instantiated with the keyword new, followed by the name of the class and a heap of parentheses $jordan = new Nbaplayer ("Jordan", "198cm", "98kg", "Bull", "23"); $james = new Nbaplayer ("James", "203cm", "120kg", "Heat", "6"); The member properties in the object are accessed by using the symbol To access static properties outside the class definition, you can access static members of the class by using the class name plus: operator: echo Nbaplayer:: $president. " Before change "." \ n "; Nbaplayer::changepresident ("Aadam siver"); echo Nbaplayer:: $president. " \ n "; echo Human:: $sValue. " \ n "; echo "Jordan:" $jordan->president. " \ n "; echo "James:" $james->president. " \ n "; echo $jordan->name. " \ n "; echo $jordan->getage (); $jordan->info (); $jordan->eat ("Apple"); Properties and methods defined in the parent class can be accessed directly on the object in the child class The member methods in the object are accessed by using the symbol $jordan->dribble (); $jordan->dunk (); $jordan->jump (); $jordan->pass (); $jordan->run (); $jordan->shoot (); // Each time an object is instantiated with new, the constructor is called with the argument list following the class name $james = new Nbaplayer ("James", "203cm", "120kg", "Heat", "6"); echo $james->name. " \ n "; By setting the variable to null, you can proceed to the call of the destructor The destructor is triggered when the object is no longer in use $james 1 = $james; $james 2 = & $james; $james 2 = null; $james 1 = null; echo "From now on James would not be used.\n"; ?>

A simple example of PHP object-oriented programming