PHP と XML: オンライン試験と採点を実装する方法

<exam>
  <question>
    <id>1</id>
    <text>问题1的题目</text>
    <answer>A</answer>
    <choices>
      <choice>A. 选项A</choice>
      <choice>B. 选项B</choice>
      <choice>C. 选项C</choice>
      <choice>D. 选项D</choice>
    </choices>
  </question>
  <question>
    <id>2</id>
    <text>问题2的题目</text>
    <answer>B</answer>
    <choices>
      <choice>A. 选项A</choice>
      <choice>B. 选项B</choice>
      <choice>C. 选项C</choice>
      <choice>D. 选项D</choice>
    </choices>
  </question>
  ...
</exam>

<?php
$xml = simplexml_load_file('exam.xml');

foreach ($xml->question as $question) {
  echo "<p>{$question->text}</p>";
  echo "<ul>";
  foreach ($question->choices->choice as $choice) {
    echo "<li>{$choice}</li>";
  }
  echo "</ul>";
}
?>

<?php
$xml = simplexml_load_file('exam.xml');
$totalScore = 0;

foreach ($xml->question as $question) {
  $questionId = (int) $question->id;
  $studentAnswer = $_POST['question_' . $questionId];
  $correctAnswer = (string) $question->answer;

  if ($studentAnswer == $correctAnswer) {
    $totalScore += 1;
  }
}

echo "总分数：{$totalScore}";
?>