Php - robot name - cannot pass last test - name has to be unique

Programming PHP
1

Hi,

I’m supposed to create a robot name and that works. I can also replace it by a new one.
But, the name has to be unique. To do so, I’ve created an array and I push the new name into the array after I’ve checked it doesn’t exist there already with in_array().
It works in test 5 and I can see the count of the array growing as new names are added. I does not work however in test 6 and I can see that the count of the array remains 1, new names are not added, the array seems to be recreated each time functions are called.
I don’t know why. I’m quite new to classes and I don’t find the info I need. Maybe a good link would help me?

Here’ s the code:

class Robot
{    
    function __construct() {
        $this->allNames = array();
        $this->name = $this->setName();
    }
    private function createName()  {
        $robotName = $this->createRandomChar() ;
        $robotName .= $this->createRandomChar();
        $robotName .= rand(100, 999);
        $result = $this->compareToAllNames($robotName);
        return ($result) ? $this->createName() : $robotName;        
    }
    private function setName() : string {
        $this->name = $this->createName();
        $this->setAllNames($this->name);
        return $this->name;
    }
    public function getName(): string {
        return $this->name;
    }
    private function setAllNames($newName) {
        array_push($this->allNames, $newName);            
        echo "count allNames: " . count($this->allNames) . "\n";
        return $this->allNames;
    }
    private function compareToAllNames($name) : bool {
        return in_array($name, $this->allNames); 
    }
    private function createRandomChar() : string {
        return chr(rand(65, 90));
    }    
    public function reset(): void {
        $robotName = $this->getName();
        $robotName = $this->setName();
    }
}

Here is test 5 that I’m passing :


Test 5 : Name aren't recycled

$names = [];

for ($i = 0; $i < 10000; $i++) {
    $name = $this->robot->getName();
    $this->assertFalse(isset($names[$name]), sprintf('Name %s reissued after Reset.', $name));
    $names[$name] = true;
    $this->robot->reset();
}

### Your Output

count allNames: 1 
count allNames: 2 
count allNames: 3 
count allNames: 4 
count allNames: 5 
count allNames: 6 
count allNames: 7 
count allNames: 8 
count allNames: 9 
count allNames: 10

And the last one I’m not passing :

Test 6 : Name uniqueness many robots

Code Run

$names = [];

for ($i = 0; $i < 10000; $i++) {
    $name = (new Robot())->getName();
    $this->assertFalse(isset($names[$name]), sprintf('Name %s reissued after %d robots', $name, $i));
    $names[$name] = true;
}

Test Failure

RobotNameTest::testNameUniquenessManyRobots
Name JA754 reissued after 1404 robots
Failed asserting that true is false.

RobotNameTest.php:111

Your Output

count allNames: 1
count allNames: 1
count allNames: 1
count allNames: 1
count allNames: 1
count allNames: 1
count allNames: 1

The tests go on for 10000 names.
I’m out of my depth.
Can you help me?

Thank you,
Karin

2

The problem is that the allNames array has to remember the names for every robot. The way it’s defined:

means that each robot gets a different allNames array.

I suggest you do some reading in the PHP docs:

3

I read your suggestions and solved it with the static keyword and then referred to the array with self::array in the functions below.

I had a question but I can discuss that with my mentor so I’m good here. I’m leaving the code for others who might be struggling with the same problem.

class Robot
{    
    public static $allRobotNames = array();
    
    function __construct() {
        $this->name = $this->setName();
    }
    private function createName()  {
        $robotName = $this->createRandomChar() ;
        $robotName .= $this->createRandomChar();
        $robotName .= rand(100, 999);
        $result = $this->compareToAllNames($robotName);
        return ($result) ? $this->createName() : $robotName;        
    }
    private function setName() : string {
        $this->name = $this->createName();
        $this->setAllNames($this->name);
        return $this->name;
    }
    public function getName(): string {
        return $this->name;
    }
    private function setAllNames($newName) {
        array_push(self::$allRobotNames, $newName);            
    }
    private function compareToAllNames($name) : bool {
        return in_array($name, self::$allRobotNames); 
    }
    private function createRandomChar() : string {
        return chr(rand(65, 90));
    }    
    public function reset(): void {
        $robotName = $this->getName();
        $robotName = $this->setName();
    }
}

Thanks for helping out!
Greets,
Karin