PHP interface resizable: Resizing functionality in the square class

Last update on May 29 2025 13:10:27 (UTC/GMT +8 hours)

4. Resizable Interface with Square Class

Write a PHP interface called 'Resizable' with a method 'resize()'. Implement the 'Resizable' interface in a class called 'Square' and add functionality to resize the square.

Sample Solution:

PHP Code :

<?php
interface Resizable {
    public function resize($percentage);
}

class Square implements Resizable {
    private $side;

    public function __construct($side) {
        $this->side = $side;
    }

    public function resize($percentage) {
        $this->side = $this->side * ($percentage / 100);
    }

    public function getArea() {
        return pow($this->side, 2);
    }

    public function getSide() {
        return $this->side;
    }
}

$square = new Square(10);
echo "Initial Side Length: " . $square->getSide() . "</br>";

$square->resize(60); // Resize the square to 60% of its original size
echo "Resized Side Length: " . $square->getSide() . "</br>";

echo "Area: " . $square->getArea() . "</br>";
?>

Sample Output:

Initial Side Length: 10
Resized Side Length: 6
Area: 36

Explanation:

In the above exercise -

The Resizable interface defines a contract with a single method resize(). Any class that implements this interface must implement the resize() method.
The "Square" class implements the Resizable interface and provides its own implementation for the resize() method. It also has a private property $side to represent the sides of the square.
The resize() method in the Square class resizes the square by adjusting its side length based on the provided percentage.
The getArea() method calculates and returns the square area using the formula: side * side.
The getSide() method returns the current square side length.

Flowchart:

For more Practice: Solve these Related Problems:

Write a PHP interface that defines a resize method and implement it in a Square class that changes its side length by a given factor.
Write a PHP program that tests the resizing method by increasing and decreasing the dimensions of a Square object repeatedly.
Write a PHP class that implements the Resizable interface and adds validation to prevent resizing to a negative size.
Write a PHP script to simulate batch resizing of multiple Square objects and display their new areas.

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