how to create default value for for an object? PHP - php

Question

let's say I have a Human class which has the variable of $gender which doesn't have any value assigned into it. Human has a constructor with the parameter of age, gender, height and weight.
I have another class called Female which inheritance from Human but now the Female class is overriding the $gender variable with a string of Female.
When I create the object let's say $f = new Female(12, 'female', 123, 40);
How can I skip typing the female when creating the object?
I thought we need to create another new constructor in Female class which I did and in the Female class constructor's parameter I have age, gender = 'female', height and weight but this doesn't seem to work.
I tried leaving the gender part empty when creating the object or tried entering empty string such as "".
Can someone give me a hand please? Thanks a lot.
Code for my human class
class Human {
protected $age = 0;
protected $gender;
protected $height_in_cm;
protected $weight_in_kg;
function __construct($age, $gender, $heightCM, $weightKG)
{
$this->age = $age;
$this->gender = $gender;
$this->height_in_cm = $heightCM;
$this->weight_in_kg = $weightKG;
}
/**
* #return int
*/
public function getAge()
{
return $this->age;
}
/**
* #return string
*/
public function getGender()
{
return $this->gender;
}
}
Code for Female class
require_once('Human.php');
class Female extends Human{
protected $gender = 'female';
function __construct($age, $gender = 'female', $heightCM, $weightKG)
{
$this->age = $age;
$this->gender = $gender;
$this->height_in_cm = $heightCM;
$this->weight_in_kg = $weightKG;
}
}
$f = new Female(12,'female',123,40);
echo "Your gender is ". $f->getGender()."<br>";

Answer 1

Simply override the constructor:
class Human {
public function __construct($age, $gender, $height, $weight) {
}
}
class Female extends Human {
public function __construct($age, $height, $weight) {
parent::__construct($age, 'Female', $height, $weight);
}
}

Answer 2

You can just set the value in the extended class:
// If it should be possible to instantiate the Human
// class then remove the "abstract" thing at set the
// "gender" property in the constructer
abstract class Human {
protected $gender;
protected $age;
public function __construct($age) {
$this->age = $age;
}
}
class Female extends Human {
protected $gender = "Female";
}
class Male extends Human {
protected $gender = "Male";
}
Although this works, it really does not make that much sense. The class itself tells you what gender the human is, so you can just call $human instanceof Female.
$person = new Female(18);
if ($person instanceof Female) {
echo "Person is female";
}

Answer 3

You can simply overwrite the constructor:
abstract class Human
{
protected $age;
protected $gender;
protected $height;
protected $weight;
public function __construct($age, $gender, $height, $weight)
{
$this->age = $age;
$this->gender = $gender;
$this->height = $height;
$this->weight = $weight;
}
public function getGender()
{
return $this->gender;
}
}
class Female extends Human
{
public function __construct($age, $height, $weight)
{
parent::__construct($age, 'female', $height, $weight);
}
}
$female = new Female(12, 170, 60);
echo $female->getGender();

Answer 4

I think, in you constructor
__construct($var, $gender="female", $var, $var){
//rest assignment
}
should do it
alternatively, use 3 param constructor with female already set