Algorithm

First Let's look a Basic fibonacci series to get a clearer example of Fibonacci Sequence - 

 0, 1, 1, 2, 3, 5, 8, 13, 21, 34

Fibonacci Formula is: 

Fn = Fn-1 + Fn-2 

Let's See the sequence:

  • f(0) = 0 (assume)
  • f(1) = 1
  • f(2) = f(1) + f(0) = 1
  • f(3) = f(2) + f(1) = 1 + 1 = 2
  • f(4) = f(3) + f(2) = 2 + 1 = 3
  • f(5) = f(4) + f(3) = 3 + 2 = 5
  • f(6) = f(5) + f(4) = 5 + 3 = 8
  • f(7) = f(6) + f(5) = 8 + 5 = 13
  • f(8) = f(7) + f(6) = 13 + 8 = 21
  • and ongoging like this Fn = Fn-1 + Fn-2

Code Examples

#1 Code Example with PHP Programming

Code - PHP Programming


function fibonacci($howMany) {
    $i = 1;
    $n1 = 0;
    $n2 = 1;
    $nextNo;
    
    echo "Fibonacci Series Are : ";

    for ($i = 1; $i  < = $howMany; ++$i) {
        echo $n1 . ', ';

        $nextNo = $n1 + $n2;
        
        $n1 = $n2;
        $n2 = $nextNo;
    }
}

echo fibonacci(10); // 0, 1, 1, 2, 3, 5, 8, 13, 21, 34
Copy The Code & Try With Live Editor

Input

x
–
+
cmd
10

Output

x
–
+
cmd
0, 1, 1, 2, 3, 5, 8, 13, 21, 34

#2 Fibonacci Series using PHP with Array and Class

Code - PHP Programming


declare(strict_types=1);

namespace App\PhpTest;

class Fibonacci
{
    public array $numbers;

    public function __construct()
    {
        $this->numbers = [];
    }

    /**
     * Generate fibonacci number series.
     *
     * @param integer $limit
     * @return self
     */
    public function generate(int $limit = 10): self
    {
        $firstNum  = 0;
        $secondNum = 1;
        $fib       = 0;

        // Add the initial numbers also in the fib array.
        $this->numbers[] = $firstNum;
        if ($limit === 1) {
            return $this;
        }

        $this->numbers[] = $secondNum;

        for ($i = 2; $i  <  $limit; $i++) {
            $fib       = $firstNum + $secondNum;
            $firstNum  = $secondNum;
            $secondNum = $fib;

            $this->numbers[] = $fib;
        }


        return $this;
    }

    /**
     * Converts generated results to array.
     *
     * @return array
     */
    public function toArray(): array
    {
        return (array) $this->numbers;
    }
}


// Then use anywhere like so - 
$fibonacci = new Fibonacci();
$fibonacci->generate(10)->toArray();
Copy The Code & Try With Live Editor

Input

x
–
+
cmd
10

Output

x
–
+
cmd
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34]

#3 Writing Test code for above fibonacci number series in PHP

Code - PHP Programming


declare(strict_types=1);

namespace App\PhpTest\Tests;

use App\PhpTest\Fibonacci;
use PHPUnit\Framework\TestCase;

class FibonacciTest extends TestCase
{
    public Fibonacci $fibonacci;

    /**
     * This method is called before each test.
     */
    protected function setUp(): void
    {
        $this->fibonacci = new Fibonacci();
    }

    /**
     * Test if fibonacci numbers generated properly.
     *
     * @dataProvider dataProviderForCheckFibonacciNumbers
     */
    public function testCheckFibonacciNumber(int $limit = 10, array $expectation): void
    {
        $this->assertEquals(
            $expectation,
            $this->fibonacci->generate($limit)->toArray()
        );
    }

    public function dataProviderForCheckFibonacciNumbers(): array
    {
        return [
            'Get 1 fibonacci numbers are:' => [1, [0]],
            'Get 2 fibonacci numbers are:' => [2, [0, 1]],
            'Get 10 fibonacci numbers are:' => [10, [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]],
        ];
    }
}
Copy The Code & Try With Live Editor

Input

x
–
+
cmd
10

Output

x
–
+
cmd
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34]
Advertisements

Demonstration

Fibonacci Problem Solution using PHP Language

Previous
PHP Reminder Example Solution
Next
Write a PHP Code to find the numbers with less occurance start to finish with number of occurance