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PHP find output programs (Constructors and Destructors) | set 3

Find the output of PHP programs | Constructors & Destructors | Set 3: Enhance the knowledge of PHP Constructors & Destructors by solving and finding the output of some PHP programs.
Submitted by Nidhi, on January 28, 2021

Question 1:

<?php
    class Sample
    {
        public $VAL;
    
        public function Sample()
        {
            $this->VAL = 10;
        }
        public function __construct($A)
        {
            $this->VAL = $A;
        }
        public function print ()
        {
            print ("$this->VAL<br>");
        }
    }
    
    $OB1 = new Sample();
    $OB2 = new Sample(20);
    
    $OB1->print();
    $OB2->print();
?>

Output:

PHP Fatal error:  Uncaught ArgumentCountError: Too few arguments to 
function Sample::__construct(), 0 passed in /home/
main.php on line 20 and exactly 1 expected in /home/main.php:10
Stack trace:
#0 /home/main.php(20): Sample->__construct()
#1 {main}
  thrown in /home/main.php on line 10

Explanation:

The above program will generate syntax error because we created constructor using __construct() with an argument, but we created object $OB1 with no argument that's why it will generate a syntax error. Because If we defined more than one constructor in a class, but constructor defined using __construct() will always call, other constructors can be defined but cannot be called.

Question 2:

<?php
    class Sample
    {
        public $VAL;
    
        public function __construct($A)
        {
            $this->VAL = $A;
        }
        public function print ()
        {
            print ("$this->VAL<br>");
        }
    }
    
    $OBJ_ARR = array(
        new Sample(10) ,
        new Sample(20) ,
        new Sample(30)
    );
    
    $OBJ_ARR[0]->print();
    $OBJ_ARR[1]->print();
    $OBJ_ARR[2]->print();
?>

Output:

10
20
30

Explanation:

In the above program, we created a class Sample that contains data member $VAL, and a constructor and a method print().

The constructor will initialize the data member and print() method will print the value of data member $VAL. Then we created an array of objects and initialized with different values and print them.

Question 3:

<?php
    class Sample
    {
        public $VAL;
        public function __construct($A)
        {
            $this->VAL = $A;
            echo "Constructor called<br>";
        }
        public function __destruct()
        {
            echo "Destructor called<br>";
        }
        public function print ()
        {
            print ("$this->VAL<br>");
        }
    }
    
    $OBJ_ARR = array(
        new Sample(10) ,
        new Sample(20) ,
        new Sample(30)
    );
    
    $OBJ_ARR[0]->print();
    $OBJ_ARR[1]->print();
    $OBJ_ARR[2]->print();
?>

Output:

Constructor called
Constructor called
Constructor called
10
20
30
Destructor called
Destructor called
Destructor called

Explanation:

In the above program, we created a class Sample that contains data member $VAL, constructor, destructor, and a method print().

The constructor will initialize the data member and print() method will print the value of data member $VAL, and destructor called when the scope of the object gets finished. Then we created an array of objects and initialized with different values and print them.

Question 4:

<?php
    class Employee
    {
        public $ID;
        public $NAME;
        public $SALARY;
    
        public function __construct($I, $N, $S)
        {
            $this->ID = $I;
            $this->NAME = $N;
            $this->SALARY = $S;
        }
    
        public function printEmpDetail()
        {
            printf("<BR>ID: %d, Name:%s, Salary:%s", $this->ID, $this->NAME, $this->SALARY);
        }
    }
    
    $OBJ1 = new Employee(101, "ROHIT", 1000);
    $OBJ2 = new Employee(102, "SHIKHAR", 800);
    $OBJ3 = new Employee(103, "VIRAT", 1500);
    
    $OBJ1->printEmpDetail();
    $OBJ2->printEmpDetail();
    $OBJ3->printEmpDetail();
?>

Output:

ID: 101, Name:ROHIT, Salary:1000
ID: 102, Name:SHIKHAR, Salary:800
ID: 103, Name:VIRAT, Salary:1500

Explanation:

In the above program, we created a class Employee that contains data members $ID, $NAME, $SALARY, and we created constructor and printEmpDetail() function to print the employee details.

Then we created three objects with different values and print them using printEmpDetail() on the webpage.

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