PHP函数排序错误

我必须通过PHP测试我写的程序，但它没有返回一个真实的结果，我无法修复错误。

我有一组登机牌，我必须按照城市的顺序对它们进行排序获取数组:

每个登机牌的结束城市是下一个元素的开始城市

<?php

class Application
{
    /** @var int */
    public $nbCards;
    /** @var BoardingCard[] */
    protected $boardingCards;
    /** @var City[] */
    public $cities;
    /** @var  City */
    private $startPoint;
    /** @var  City */
    private $endPoint;
    public function getCitiesAsString()
    {
        $names = [];
        foreach (self::getCities() as $index => $city) {
            $names[] = $index.'-'.$city->getName();
        }
        return implode(" - ", $names);
     }
    /**
     * Application constructor.
     */
    public function __construct()
    {
        $this->boardingCards = [];
        $this->cities = [];
    }
    /**
     * @return BoardingCard[]
     */
    public function getBoardingCards()
    {
        return $this->boardingCards;
    }
    /**
     * @param BoardingCard[] $boardingCards
     */
    public function setBoardingCards($boardingCards)
    {
        $this->boardingCards = $boardingCards;
    }
    /**
     * @return City[]
     */
    public function getCities()
    {
        return $this->cities;
    }
    public function addCity($city)
    {
        $this->cities[] = $city;
    }
    public function addBoardingCards($boardingCard)
    {
        $this->boardingCards[] = $boardingCard;
    }
    /**
     * initiate the application
     */
    public function run()
    {
        echo "***********Welcome******* 'n";
        do {
            echo "how many cities do you want to add? 'n";
            $handle = fopen("php://stdin", "r");
            $nbCities = trim(fgets($handle));
        } while (empty($nbCities) || $nbCities <= 0);
        for ($i = 1; $i <= $nbCities; $i++) {
            $city = new City();
            do {
                echo "Enter the name of the city number $i: 'n";
                $name = trim(fgets($handle));
            } while ($name == '');
            $city->setName($name);
            $this->addCity($city);
        }
        $this->nbCards = count($this->getCities()) - 1;
        for ($i = 0; $i < $this->nbCards; $i++) {
            $boardingCard = new BoardingCard();
            //*********** get boarding card Type ***********
            do {
                echo "Enter the boarding card (".($i + 1).") type    [".BoardingCard::getTypesAsString()."]: ";
                $type = strtolower(trim(fgets($handle)));
            } while (array_search($type, BoardingCard::getTypes()) === false);
            $boardingCard->setType($type);
            // *********** get start city ***********
            do {
                echo "Enter the boarding card (".($i + 1).") start city from the list: ".$this->getCitiesAsString();
                $index = trim(fgets($handle));
            } while (!isset($this->cities[$index]));
            $boardingCard->setStartCity($this->cities[$index]);
            //*********** get end city ***********
            do {
                echo "Enter the boarding card (".($i + 1).")  end city from the list: ".$this->getCitiesAsString();
                $index = trim(fgets($handle));
            } while (!isset($this->cities[$index]) || $this->cities[$index]->getName() ==
                $boardingCard->getStartCity()->getName()
            );
            $boardingCard->setEndCity($this->cities[$index]);
            // *********** get seat number ***********
            do {
                echo "Enter the seat number: ";
                $seatNumber = trim(fgets($handle));
            } while (empty($seatNumber));
            $boardingCard->setSeatNb($seatNumber);
            if ($boardingCard->getType() == BoardingCard::TYPE_TRAIN) {
                do {
                    echo "Enter the train number: ";
                    $trainNbr = trim(fgets($handle));
                } while (empty($trainNbr));
                $boardingCard->setTrainNb($trainNbr);
            } elseif ($boardingCard->getType() == BoardingCard::TYPE_BUS) {
                do {
                    echo "Enter the bus name: ";
                    $busName = trim(fgets($handle));
                } while (empty($busName));
                $boardingCard->setBusName($busName);
            } else {
                do {
                    echo "Enter the flight number: ";
                    $flightNbr = trim(fgets($handle));
                } while (empty($flightNbr));
                $boardingCard->setFlightNb($flightNbr);
                do {
                    echo "Enter the gate number: ";
                    $gateNbr = trim(fgets($handle));
                } while (empty($gateNbr));
                $boardingCard->setGateNb($gateNbr);
                do {
                    echo "Enter the counter number: ";
                    $counterNbr = trim(fgets($handle));
                } while (empty($counterNbr));
                $boardingCard->setCounterNb($counterNbr);
            }
            $this->addBoardingCards($boardingCard);
        }
        echo " 'n";
        do {
            echo "Enter your journey start City from the list: ".self::getCitiesAsString();
            $index = trim(fgets($handle));
        } while (!isset($this->cities[$index]));
        $this->setStartPoint($this->cities[$index]);
        do {
            echo "Enter your journey end City from the list: ".self::getCitiesAsString();
            $index = trim(fgets($handle));
        } while (!isset($this->cities[$index]) || $this->cities[$index]->getName() == $this->getStartPoint()->getName(
            ));
        $this->setEndPoint($this->cities[$index]);
    }
    public function showCards()
    {
        foreach ($this->boardingCards as $key => $boardingCard) {
            echo $key."- ".$boardingCard->getDescription()."'n";
        }
    }
    public function sort()
    {
        $i = 0;
        $j = 0;
        $tempStartPoint = $this->getStartPoint();
        $sorted = false;
        while ($sorted == false ) {
            echo "temp start point : ".$tempStartPoint->getName();
            if (strcmp($tempStartPoint->getName(), $this->boardingCards[$i]->getStartCity()->getName())) {
                $temp = $this->boardingCards[$j];
                $this->boardingCards[$j] = $this->boardingCards[$i];
                $this->boardingCards[$i] = $temp;
                echo "on a permute  : ".$this->boardingCards[$j]->getStartCity()->getName()." par : ".$this->boardingCards[$i]->getStartCity()->getName()."'n";
                echo "temp start point : ".$tempStartPoint->getName();
                $tempStartPoint = $this->boardingCards[$j]->getEndCity();
                echo "temp start point : ".$tempStartPoint->getName();
                $j++;
                $i = $j;
            }
            else {
                $i++;
            }
            if ($j == ($this->nbCards - 1)) {
                $sorted = true;
            }
        }

    }
    /**
     * @return City
     */
    public function getStartPoint()
    {
        return $this->startPoint;
    }
    /**
     * @param City $startPoint
     */
    public function setStartPoint($startPoint)
    {
        $this->startPoint = $startPoint;
    }
    /**
     * @return City
     */
    public function getEndPoint()
    {
        return $this->endPoint;
    }
    /**
     * @param City $endPoint
     */
    public function setEndPoint($endPoint)
    {
        $this->endPoint = $endPoint;
    }
}