對于多項選擇考試，我將數據存儲在文件中。.txt我有8個文件，其中存儲了2個或更多數字。txt 文件的名稱是.txt1.txt, 2.txt, 3.txt ...每個 txt 文件中的第一個數字始終是正確的答案。我想將第一個數字與該txt文件的最后一個數字進行比較。foreach($all_files as $file) {    $each_file = file_get_contents($file);    $choosen_answer = substr($each_file, -1); // last number is the number user has choosen    $correct_answer = substr($each_file, 0,1); // first number is the correct answer    // output the answers    echo '<span class="choosen_answer">'.$choosen_answer.'</span>';     echo '<span class="correct_answer">'.$correct_answer.'</span>';    $wrong = 0;    if($choosen_answer != $correct_answer) { // compare the 2 values        $wrong++;        echo '<span class="wrong text-danger">Wrong</span>';    }    else {        echo '<span class="correct text-success">Correct</span>';    }}echo count($wrong); // this should give me the number of wrong answers, but it does not...我想計算錯誤答案的數量，我為此嘗試了，但它沒有給我錯誤答案的數量。count($wrong);所以我需要什么：如果問題回答錯誤，它應該給我數字383每個 txt 文件如下所示：02 // 0 is the correct answer, 2 is the answer from the user. I compare 0 with 2. So wrong answer或14 // 1 is the correct answer. 4 is the answer of the user. I compare 1 with 4. So wrong answer或22 // 2 is the correct answer. 2 is also the answer of the user. So correct answer