<?php

//答案类
class Answer implements JsonSerializable
{
    private $answer_id;
    private $question_id;
    private $answer;
    private $is_true;

    /**
     * Answer constructor.
     * @param $answer_id
     * @param $question_id
     * @param $answer
     * @param $is_true
     */
    public function __construct($answer_id, $question_id, $answer, $is_true)
    {
        $this->answer_id = $answer_id;
        $this->question_id = $question_id;
        $this->answer = $answer;
        $this->is_true = $is_true;
    }

    /**
     * @return mixed
     */
    public function getAnswerId()
    {
        return $this->answer_id;
    }

    /**
     * @return mixed
     */
    public function getQuestionId()
    {
        return $this->question_id;
    }

    /**
     * @return mixed
     */
    public function getAnswer()
    {
        return $this->answer;
    }

    /**
     * @return mixed
     */
    public function getIsTrue()
    {
        return $this->is_true;
    }

    public function jsonSerialize()
    {
        $data = [];
        foreach ($this as $key => $val) {
            if ($val !== null) $data[$key] = $val;
        }
        return $data;
    }
}